She's different from Athel, in that she's not really an AOE damage dealer. Unless you can put 4+ debuffs on enemies, she's pretty much a single target nuker. 

That said, I do like her, especially for her self-boost. Early on, when you have a hard time getting enough crit rate and crit damage, it can be very valuable from gearing standpoint. 

is she worth using prior to hydra? yes.

is she worth using at this moment? maybe not.

oboro is a better champion overall when compared to athel, but she does come with a few drawbacks. first, she needs to be in a debuff-heavy team in order to really shine and you're somewhat lacking in debuffers. it's certainly possible to trigger her aoe a1, but i expect you'll be short on debuffs more than you'd like. second, oboro is one of those champs who can't decide whether she wants to be dps or a debuffer. you can always choose to ignore one or the other (in her case, dps would be the way to go), but if you want to do both, you'll be stretching her stats pretty thin. she also can't be used as a campaign farmer, but that's only an issue if you were thinking of pinching some gear off athel to move to oboro instead.

having said all that, oboro is still a solid champion. her multipliers are all quite good, you don't need to worry about affinity matchups, and her veil and revive buffs make her harder to kill than your standard dps champion. she's definitely worth using; i just think you might want to build a few other champions before you worried about gearing her (unless you have gear already levelled that would suit her, in which case go wild). i'd be interested in seeing who else you have in your collection but barring any hidden gems there, my advice would be to grind deadlands until you get a warmaiden drop.

I use Oboro as a mischief tank for Hydra, I find her great in that role.  There are some very good videos on Oboro's use in Hydra.