I mean... at least it has mouse gestures. Hard to knock it for being not feature-rich enough when it has a feature no other browser has by default (except Vivaldi, which has Opera lineage).
a) This built-in feature is way below the standards trivially achievable via extensions in Firefox, Chrome etc.
b) It's a downgrade in relation to what Opera itself used to offer in the past (and then, if I recall, got so stripped of functionalities it didn't even support bookmarks at some point).