which is a more useful moveset overall?

"Overall" for me it's B/SE
It's super effective into tons of desirable targets and its raw damage is on par with B/C into targets weak to Dark.

B/SE

For me, its B/C.
It is fine to have a strong 3-bar-move for sweeping out gyms. If i need rock, i can use golem. If i need dark, i have no real alternative to tyranitar.

Right now it's B/SE with the legendary raids as you can use it for every single legendary bird. Golem technically works on Moltres/Arti but would get demolished very very quickly compared to Ttar.

During normal times I would probably prefer B/C, as especially on the final motivation round in gyms you may be able to one shot 3 targets in a row with a crunch.

B/SE as a bird killer and better gym sweeper. But B/C as the best MS against Mewtwo. I got 67 CTMs and growing. I'll change all my SEs into Crunch when Mewtwo is out.

Since I dodged often, especially on charged moves, B/SE for me. Crunch is pretty slow for a 3-bar move ( 3.2s vs SE's 2.3s ), so much higher risk of getting hit by opponent's charged moves.

Btw, against neutral dps target, B/SE is slightly better than B/Cr ( https://youtu.be/tqsrmv18Xsw )