God bless you

[mtbc]

If people sneeze then it feels polite to say bless you but also so very silly. I don't think they're at risk of lethal plague or cardiac arrest or soul displacement or anything else popularly thought to relate to the sense of the wish and I suspect nobody else does either. It also sounds a bit impolitely imperative in any brief form. Am I interpreting the response wrongly? Has it a worthy successor?