For everything that's not realistically going over the 1 billion mark, I think you could make better money ( because I would buy, and proly other lazy people could as well ) putting the item in the priced items chest rather than start a 7 days auction.
Tbh, everything auctioned for under 50-100 millions would sell faster if people just sell it straigh away; as a example, I'm more than happy to throw 100-300 millions if I can put my hands on some crafting item NOW, and can't be bothered to overbid a 10 millions offer if I have to wait half a week and keep a eye over the item.
To me the logic behind putting things in the 7 day auction chest is to get an idea of what its worth and also to get the max possible from it. Part of being able to sell an item for hundreds of millions vs the seller just getting the same item himself is convenience. So your point that the auction chest will result in lower prices because using it is inconvenient compared to the market chest makes sense.