Hello!
A confirm button for buyout on the auction house would be a great quality of life change.
I recently ran into an issue where I inspected an item, then tried to go to the next page of the auction house. With a slight slip, I accidentally purchased that item for more than double its worth. As I was saving for an item at the time, it had completely wiped out a couple of weeks of playing. A very kind player bailed me out and purchased the item for what I purchased it for, but if that didn't happen, I might have quit playing there and then.
I've also seen multiple people put up items with high buyouts, specifically hoping people misclick and buy them.
Support mentioned I should put this in suggestions. I definitely think a confirm button would be good.
I don't hate the idea of changing the AH UI, but I'd rather see an overhaul where it's mainly just made harder to misclick by moving these buttons further apart.
It could also be fine with a confirm for something like large values only.