This is nothing new. I have posted this before. This is pretty gimmicky, nothing that can be relied on and easily beat out.
EX TKP stops a tech roll. It does not stop wake up attacks.
You can still be hit out of this. Try doing this to a Mileena player.
Yes this "can" work and you can catch someone off guard. But this is definitely not something you can loop over and over in the corner. Against top players you will be lucky enough to get away with this once. The combo itself is unbreakable which is very nice. But here is why this can be beat out 10/10 times:
Your opponent just needs to stay on the ground and hold block.
They will stay lying on the ground and will be able to block any move that can hit them. ( d2 , tk moves etc)
If they stay on the ground, almost all normals,grabs and block strings will whiff over them including the unblockable.
Now you might think " Oh I can out play them and cancel the unblockable and try something else". Once again, your opponent just needs to wait for you to make the first move and hold block.
Now, any good player who knows what ermac can do, especially in the corner, will not fall for this and will just wait this out on the ground blocking waiting for you to attack. Or they will be able to find an opening when you are canceling the unblockable. If you are beating someone with this, it is only because they have never seen it before.