-Wins against all Deoxys (except to Deoxy-A, but then they will not get SR up) due to X-Scissor + ES forcing them to only get 1 layer of entry hazards or none at all if they choose to Superpower (which you survive), but you will die to Superpower + ES from Deoxy-A, but in the process breaking its sash, so just switch in a priority/pursuit user.
And in case of overprediction?
Running to same people time after time (no need to talk about how much this happens in ubers) creates a mindgame of KO Arceus/Get Stealth Rock down for you opponet.
All these actions assumed after Deo-A using Superpower and Arc using X-Scizzor.
If they Extremespeed and you switch, you basically win,.
If they use Stealth Rock and you switch, well, they get the rocks and you their lead.
If they use Stealth Rock and you attack, Deoxys get extremely annoyed.
But if you both use Extremespeed, Deoxys wins.
Whether or not you might switch depends a lot from the team: having Forretress makes opposition's rocks slightly less devastating, or even more, if they have no Giratina. Also, if you rely much on Arceus to revenge certain threaths, risking rocks might be worth it. If you happen to have other revenge killers or no spinner + some flyers, keeping Arceus just in case should be considered - expecially if your opponet has seen yuo switching Arceus from current situation before.
Also, it is worth noticing, that Deoxys-A can severely weaken Tyranitar on switch. Unless it carries non-standard Fire punch, Scizor and Metagross will be relatively safe - as not even -1 Superpower + -2 Superpower KO unless both crit.
(As I found no uber set for Ttar, 160 HP CBtar was used for the calculation)
-1 Superpower aganist Tyranitar 108.1% - 128.1% (Deo is KO'd by sandstorm)
So no pursuiter is threathened by lead Deoxys-A running the standard set, as Tyranitar's Sandstorm KO's it even in the unlikely event of it choosing to Superpower on the predicted switch, and Scizor and Metagross can take any 2 of its attacks, and therefore must only use priority on Deoxys if they are in prime need of preventing Stealth Rock.
(Obviously in a scenario, where they didn't SR on the Switch already)
So, my point was: Even if they Superpower, your switch gives them a chance to get their hazards down. This is still risky, as you might stay and Extremespeed Deo down or use priority with your pursuiter.
But those scenarios open up different holes. Advantage is yours, as long as they don't switch in something problematic on predicted X-scizzor.