Is it bad to use a guitar on a bass amp?
It is not bad to use a guitar on a bass amp. There are some famous guitarists who have used a bass guitar with a a guitar amp. However, when using the guitar amp, it has to be turned down almost to the lowest level.
Yes because if you try to play a bass on a guitar amp, the amp won't be able to pick up the lower frequencies and it will just mess it up. It's probably vise versa for your question