It might not be totally out of place to have such an avatar; but I wrote from my solid UX background.
In services like mixers and instant exchanges, that have strong competition in the community, such avatars are purely unnecessary and could be labeled as a distraction.
Having such displays would retain users watching images and finding faults instead of going forward to transact.
If there should be an avatar or picture, it should be something showing Pablo's $325k escrow, exciting daily/monthly transaction volume, large reserve or an amazing review and not a man holding xmr and BTC.
I do get this may be what is trending right now as 'the best' for keeping people on the website and making it 'more pleasantly looking' and I do not contradict you, but I am personally pretty sick of all those minimalist designs. No matter what website you choose nowadays, it looks like a funeral. Considering the World is losing color, my personal preference is the avatar over minimalism.
I agree it could also contain some of the information you listed, such as the Escrowed amount. That would not be bad at all.
