Is there anything you can use treasures for, or is it just gold? If it's just gold, then it would be nice to have it auto-convert. If not, then at least add a category for it in the shop interface so we can separate them out easily.
I keep some treasure, so I'd not appreciate an 'auto-sell' function. You filter out treasure in your list, rather than the one in the shop, I think.
some people just like collecting things as trophies etc I guess (immersion ?)? like people who must steal every piece of cheese in skyrim.