Wait... Swain can heal with his ult during Zhonya's active???

Edit 3: I think I need to put this up front so everyone sees it first: Swain hits ult, hits Zhonya's, goes invulnerable. The ravens fly out and deal damage. This I am okay with. What I am not okay with is that they fly BACK to Swain, who is invulnerable, and they heal him.

Edit 4: Lol are you guys really gonna act like you knew a damn thing about this champion 3 patches ago? Please...

I recently had an experience during a team fight where the enemy Swain, who was very ahead (go figure), got caught out by my teammates and used Zhonya's active while his ult was active because he was about to die. My team grouped around him and waited for Zhonya's to end, only to find that doing so allowed swain to heal from ~15% to ~60% health. During that time, Swain's teammates arrived and forced a fight, and we didn't have enough burst to finish him. We lost the fight and eventually the game.

I just don't believe this should be possible at all. Basically my argument is that the point of Zhonya's active is to buy yourself some time, not to buy yourself some time AND free healing. I actually don't believe any champion should be able to heal during Zhonya's at all, just because of how extremely advantageous that is compared to champions who can utilize Zhonya's but not heal during the active.

I think there should be a double-standard when it comes to invulnerability, except in cases which the very point of the invulnerability is to heal (Vlad W for example).

Thoughts?

Edit: I should have been clearer on my main point. I think it's fine that his ult can be active during Zhonya's, but I just don't think he should be able to HEAL during the Zhonya's. He has to come close to enemies to be able to heal at all, and usually the trade-off is that he takes damage doing so. But the fact that he can just Zhonya's and heal up is just busted to me.

Edit 2 (another re-iteration): It's fine that a champion can deal damage while invulnerable, because that damage is dished out to champions who AREN'T invulnerable. But if Swain can't be affected by any other champions during Zhonya's, then why can he be affected by the birds that fly out towards enemy champions to deal damage, and then BACK to him to heal him? They should just do damage without healing him while Zhonya's is active.