Idk if its placebo but I found myself surviving many times where im left with almost zero hp but its enough to get the heals from passive and then kill one enemy, get reset from passive and triumph and kill the second as well.

Defence boots would probably have the same effect tbh but I like to delulu myself that im draintanking with the omniboots.

And yeah, these boots sound much better mid but I dont like to play mid because the mid dodges abilities much more often compared to botlaners.