Right now what makes me pissed is the actual bin/isos. You gave a good example with Burn:Cycle. I've downloaded a bin version that doesn't even run on MAME. But the same bin file runs fine on CDiEmu. It seems it's easy to mess up an image container for MAME.
Btw, .bin files seem to be supported now. (Some actually loaded for me so they don't seem to be an issue anymore)