But yes for speed bench / acceleration training there is probably nothing better than a light bar weight with medium band tension .
Now deads are a trickery beast. Deads were always my weak link of the 3 due to my L4 L5 problems I just was never good convo or sumo. Also IMO chains becomes less effective on deads given the leverage. I was always the kinda guy where if it left the floor it was coming up all the way. Speed deads with bands I think do help with that acceleration off the floor, however you really need a proper platform. There are different ways to set your bands up for speed deads just like bench. Probably a 2 phase protocol works alternating between them depending on the week or month you are in. As well as knowing where you sticking points are.
Anyway, this was the tip of the iceberg, I can do musclehead talk all day buddy feel free to hit me up anytime for that..or phone stuff too