interesting they went with Chromium on desktop when their Android browser uses (or at least used to use) Gecko.

Exactly my sentiments. Zero desire to use any form of chromium.

Is there a reason to use it over the regular TOR browser?

if i was making a crossplatform browser i’d use the OS’s default web renderer too.

i dont know of a single company that wants to secure their renderers outside of apple, microsoft, and google.

mozilla barely gets by with being a tiny marketshare and using the same security features provided by the OS.