Would you evolve this level 30 Teddiursa?

Of course as long as they aren't super rare where you are.

Edit for Blissey: Not particularly. Not terrible but it doesn't really rank.

I have a lvl 30 one myself with C/CC, and sure, it's decent into Blissey. My Machamp evo flopped again (very rare in my area), so I use it quite a bit. But it's not overwhelming by any means.

Unless candy is really rare for you though, isn't it worth to evolve when you don't even need to invest? You could end up with a strong attacker for free. Free attackers are almost as good as free food.

Yes, evolve him. IVs aren't that important for attackers.

I'll evolve lesser IVs lvl 30 mons for attacking as well.
(prestige mainly)
I don't want to power up any mons except for the big three, Dragonite, Blissey and Snorlax. (I still don't have a tyranitdoesnotexistforme.)

I already have 2 very similar evolved from lvl30 Teddi

EDIT But was lucky to get Hyperbeam on both...probably the strongest Hyperbeam in the game, once you consider STAB

Worth it, but I think Hyper Beam is better.

I'd w8 a bit.
May you get a better one^^

evolve it and hope for hyperbeam its good in the bear

It's not like you have anything to lose by evolving this Teddiursa.

If you get Counter + Hyper Beam or Close Combat, great. You've got a good Snorlax / Blissey attacker for 0 dust. If not, no big deal since you didn't have a better Teddiursa to use it on anyway, and if you're lucky enough to catch another one worth evolving that'll bump your candy count to 50 anyway.

I would evolve it, but dont power it up

I read your post that you already evolved it. You did the right thing, I think. It was already level 30, so all it cost you was the candies to evolve it. If you would have ended up with the Counter/Close Combat move set, you would have had a serviceable attacker into a lower level Blissey. I know that to be true, because I have one. Not great, but helps get the job done on a Blissey. I have to finish the Blissey off with an great Alakazam. The Ursaring is actually quite effective against a Snorlax.