late game ones have potions, but they are the weakest tier.
mostly the point is funds. Chests are your primary source of junk that the vendor takes for cash. Funds for the vendor -- you can't get enough for a short time, then suddenly you have 2 rooms that look like scrooge mcduck was playing the game.

secondary, you must loot chests to get one type of seed for crops.

unimportant but the steady supply of arrows is an honorable mention. feathers are great too, as hunting birds is tedious. don't sell a stack of 20 frost arrows short, after a few chests that is a stack of them, and those are pretty nice.

extremely nice:
- some chests have outstanding rewards. Specifically in the swamp instances, you can get full stacks of both wood and metal that are awesome time-savers. The barrels that are not-quite-chests in the BF have tin, berries, hides, and other goodies. Plains chests have crops (which can be used for seeds) and arrow materials and metal as well I think. Mistland chests have the potions and money and a variety of stuff you shouldn't need but doesn't hurt to have.