One reason could be that most of the teleports lead into a full combo punish instead of just ~10% here or there. Although the teleports themselves are usually fully punishable, they mess up the footsie game also.
Basically this. I'm fine with fighting Aquaman's shield since it's only minor damage at worst, vs certain teleports that are more like "Oh, see, you WANTED to try to start something with that B1U2 since it's safe on block, but now I'm behind you, it's unsafe on wiff, and you're gonna have to hold this full combo and this maniacal laughter."
Just my outlook anyway. It also makes zoning THAT much harder. You can sure, try to bait the teleport, but I still find that about half of Deathstrokes game is his zoning, and now you have to play a waiting game. Sure, you have to be patient anyway, but it just makes the MU harder to repeat in long succession.