I don't think there is real functional use of a bayonet if just headed to the range and stuff. But it sure is worth having a true historical setup that includes the bayonet. I have one for my Colt SP1 as well as for my AK, just look to know that it has the cool factor albeit never used.
I have a few bayonets . Notably an STG57 and a K98 bayonet . I always look for em in antique stores and amongst knife sellers at flea markets and so on.