I'm hoping this move gets a massive buff (or the movepool changes, or something) before Deoxys actually starts appearing at EX raids. It would be fun to use as a super glass cannon; ridiculous damage output offset by extreme frailty. Otherwise, I really don't see the hype lasting long for Deoxys, because (unlike Mewtwo), Deoxys won't be useful for anything in it's current state.
How bad is Psycho Boost?
It's so damn bad that even when put on the 414 attack forme of Deoxys, it still lags behind Alakazam.
Answers
I'm not saying it will be super useful for solo challenges, I'm saying if it has any usefulness whatsoever, it will only be in solo challenges. Normal forme has the same tankiness as Sharpedo and attack forme has less. If you've used Sharpedo in unique solos, you know it dies in a blink but can still help put you ahead of the clock. I can see Deoxys occupying a similar niche in the solo meta.
I've used Swellow, Slowbro, Mr. Mime, Wigglytuff, Donphan, Slaking, Ninetales, Rapidash, Meganium, Sunflora and a host of other trash attackers in unique solos. I wouldn't call any of them extremely useful just because they were able to contribute to a solo.
In the games Psycho boost is intended for a glass cannon like Deoxys, it's very powerful the first time it's used but becomes much less powerful after that. (by which time Deoxys will likely be dead anyway.)
The fact Niantic made it so bad indicates they have no intention of allowing Deoxys any relevance in the meta.