Some people won't keep hermits at all, but the blue legs in my other tanks are so tiny, I can't see how they could hurt them, but I still haven't risked it and put them in my SH tank. Plus, they'll kill your nassarius and cerith snails and steal their shells and my nassarius are too valuable to me for that.
I have a couple nassarius snails, a couple astrea snails, and a bunch of stomatella.