Because it’s not based on chromium(blink web engine), there are two other well supported web engines which browsers can be based on, WebKit (Apple), and Gecko (Mozilla).
At the end of the day, if it’s built on Blink, it’s liable to have Google break things they don’t like on the back end. Including ad blockers.
Opera used to be built on it’s own web engine (presto) but since 2013 it’s been built on Blink.
See, as a terminal foxhole player, this means something very different to me.