The string is useless in sense that it can be SS or held. That is going to be a problem for Eliot players going on the offensive. He's very linear and has to play the stun game. However, the string can be used if free canceling is implemented into it. Most chances are that your opponent will be trying to mid punch hold. You bait that and use his air throw, and they'll wish they had let you finish your string.
On this particular stage (Home) Eliot could have put Brad at the brink of his life if not killing him. When Brad got slammed through that wall there was nothing he could do but SE. Eliot had enough time to land a guaranteed attack. Or bait a hold for his throw which should grant him more guaranteed damage because of the ceiling. I am not 100% sure if his air throw has that capability. It didn't in 4 so it still may be the same.
I personally think that the string can be used against the unknowing but anyone who knows about it and can defend well, I wouldn't reccommend using it.
Also using his p+k is not all that great. As far as I know he can only go mid or low after p+k. That low is telegraphed and he's at -4 if I remember right. Plus the low punch does nothing on NH. So the mid is the best option and that will most likely be held. So you'd have to free cancel after the move most of the time even on CH. Someone who can SE and defend well will not be phased by that move or string.
This 1 move does not matter though, Eliot is ridiculous in other areas.
Oh yeah. I will say it again. I know I've said it before and some else (Drdogg maybe?). Eliot has to play doa4 when he's on the offensive. That is his 1 and only major downfall.