In practice nobody plays an electric guitar on a bass amp or the other way around. Is that because of the sound ranges? Would it destroy an amp or does one not do it because it sounds worse???

Thanks

bass amps are built for low frequencies and guitar amps for higher frequencies. you can play a guitar over a bass amp and the other way around.. but i don't think it'll sound that good. i also heard that it can fuck your amp if you run it at high volume. get yourself the right amp for your instrument, even if you play bass & guitar