I make one or two treasuries a week, mostly to post on my Facebook page for "treasury Tuesday." I keep a running list of things that I think would make good treasury themes, and I usually spend around half an hour on each one.
At this point, I don't know how much attention they get me or my shop, and they never get tons of views, but they're fun to make. And I always get a little thrill whenever one of my items is featured in a treasury, so I like to try and pass that onto someone else whenever I can.
I am lazy about keeping them updated, though...