Yes, that's why it has both and can roll both at the same time. The power is useful. More useful than Sky Attack, certainly, because Sky Attack is single-use and can miss.
Fast Encore turns bulky Pokemon trying to set hazards or recover, or literally anything using a Bug, Dark, or Ground move, into free setup bait. Taunt can't do that. You're right; hawlucha is frail, and forcing the opponent to attack it doesn't seem like the best of ideas.
I know y'all are really angry that a hawlucha doesn't always have acrobatics, but rands is different from tiers. You don't see it running seeds, do you? It isn't trying to be bulky or survive for as long as possible, and it can't use Acro immediately like it can in tiers. It's trying to set up, KO a couple of mons, and then dip with its job being done. And sometimes, it can't even set up, and acrobatics isn't useful then. Brave Bird, however, is useful out the gate before and after setting up unburden, unlike both of its other flying move options.
Both of the format heads agree about this: Hawlucha will not have enforced Acrobatics, we will not under any circumstances remove Brave Bird, and we will not remove Encore unless its winrate drops from its recent addition.
