I just like the aesthetic look of smaller stitches. It’s all personal preference. I have a high tolerance for doing a bazillion tedious stitches. For me, the process itself is very relaxing and fun – so where most people would get frustrated that the project isn’t done as quickly, I almost prefer it.
So, really, 3 reasons:
1) I have a huge stash of worsted weight and fingering weight yarn, which I also use for regular knitting and crochet.
2) I like the way stitch patterns, cables, and color change patterns look with smaller stitches – you can get more detail
3) I don’t find large stitch counts frustrating or tedious, and I’m not looking to pump out a lot of finished projects quickly
I think if I wanted to make a TON of hats or mittens to donate to a charity, I might want things to go faster with a larger gauge loom. Right now I still donate projects, but it’s not my primary reason for crafting. Most of the time I just craft for personal relaxation. 🙂
I will say I did try using my grandmother’s looms for double strand worsted weight, but I disliked how it looked so much that I frogged the whole thing and wound them back into balls. :/
I guess it’s like my aversion to the color pink – I have no real reason why, but I hate the way pink looks. And I hate the way bulky stitches look. 😛