I could be wrong since I don't PvP much, but aren't hots dispellable? If so, then this exploit is still useful in that you're giving your opponents one more thing to have to worry about dispelling.
Then again, it's probably better to spam lifebloom if there's someone dispelling all your hots. It's ridiculously efficient with the mana discount talent.
And yeah, only the highest rank of rejuv is ticking. Oh well.