It is all about sound and preference.

The PA amp is designed to cope with a much broader frequency than a guitar amp. It is also tuned differently, exaggerating specific frequencies to make the overall sound nicer.

Does that make it better ? Well that is up to you !

There are al lot of different types of amp that are used for guitar on the market. Is a Messa Better than a Marshall ? Well that is up to the guitarist to decide !