This is an interesting question to ponder, and (at least for me) you might get a different answer on different days depending on my mood and the depth of my thinking at the moment. I can think of several reasons right now, without even trying too hard because quilting really meets a lot of different needs in my live on a variety of levels. One of my quick and easy answers relates to how I started quilting in the first place.
I have sewn all my life. One of the first projects I can remember making was a sweet outfit for a barbie doll - I'm guessing I was around 7 or 8 years old and cut a piece out of one of my moms good sheets for my project. After that she was a little more careful about providing me with acceptable materials for my experiments! My mom also grew up sewing, as most girls of her age did. She never liked handwork, though, so the patchwork blankets at our house were tied with embroidery floss, except for the quilts we got from grandma. I always loved those - made of flour sacks and hand quilted. They were bright and it was fun to look at all the different prints, I think my love of all things scrappy originated with those quilts! We used and enjoyed them, and wore them down with picnics at the park, forts in the living room and overall daily abuse. So for me, quilts are meant to be used and loved - there will always be fabric to make more.
As I became a teen I continued in my love for making things and taught myself to knit and crochet. I joined a craft of the month club and learned decoupage, cross-stitch, and a host of other crafts, but always enjoyed sewing the most. In high school I made many of my own outfits, finding great joy in being original and wearing things that no one else had. I took home ec, and had a lovely teacher who was happy to teach this girl the finer points of sewing and handwork, and found some lesser known forms of needlework to challenge me with like swedish weaving and chicken scratch! I am glad she was not one of those mean ones who don't like students that know a lot already. I made a simple quilt out of rectangles for my bed, using scrap fabrics from the dresses my mom made me growing up and fabric bundles we purchased through the mail. This was in the seventies, when quilting was becoming more popular again - we used two thick poly bats and tied it with embroidery floss to make a thick warm blanket that was wonderful to sleep under on cold nights in Colorado.
I was married in a wedding gown I made myself, and as my girls were born enjoyed making them dresses and nighties, but found less and less time as my family grew for being creative. I made a few simple comforters for our beds, including a "big girl" quilt for each of the older two when they moved to a twin size bed out of their cribs. When I was pregnant with my fourth daughter I made a wonderful friend who was absolutely in love with the idea of quilting! She persuaded me to try hand quilting.
I used a pattern from a womans magazine. I did it in red and green and chose a background fabric with little blue flowers because we were hoping for a little boy. It was an Irish chain quilt with stuffed hearts in the open area. I worked for weeks hand quilting it - I used two strands of regular sewing thread and stretched that fabric so tight in my hoop that all I could do was stab stitch up and down. I was hooked! I loved the texture that the hand quilting created. I loved the fact that I could quilt a block, and come back to it later and be able to do another - finally a chore that stayed finished! And the fact that I could be busy doing something and have a few minutes to quiet my mind and think. From there I never looked back and have always had a quilting project (or three!) to work on.
As my skills have progressed the quilting world has changed. There are so many more options now, less rules about how to do it "right". More fabric available, more tools, and more options for meeting with fellow quilters! Right now I see a lot of "Farmers Wife" projects being worked on, which is exciting. A lot of people are making these wonderful blocks, learning to quilt with templates, which for many is a new skill - for me it's going back to where I started! (No, I'm not joining in, I still have my Dear Jane in progress, so I'm not going to go there!) I'm thrilled to sit by and watch while a new generation of quilters is learning how to use the tools I started out with - and really happy that the traditional methods still are relevant in a world of rotary cutters and fast piecing.
I still love scrappy quilts, most of my stash consists of pieces that are less than 1/2 a yard! I now machine quilt more than I hand quilt, though I do love both. Quilting fills a need in my life to create something that will last longer than this day, week, or month. Quilting also gives me an opportunity to play with color, contrast, pattern. It quiets my mind, allows my thoughts to percolate and develop and centers me. It gives me a social outlet as I meet other quilters and am able to develop friendships. I quilt because it gives an added depth to my life, allowing me to be creative, it challenges me to develop skills and expertise beyond what I already have and it allows me to touch the lives of others.
(please forgive the bad pictures, but I started quilting before digital cameras...these pictures are in no particular timeline, just some of my favorites I have made!)