I actually have a Glock 21 that is water-transfer Camo (bird shit motif) with night sights, extended mag release, lanyard ring, extended slide release, all capped off with an under mount (modified Picatinny) KaBar miniature bayonet....devilishly nasty looking
I just looked at them,,, you are right they would be nasty
On Gunbroker someone was selling replicas of flint lock pistols with bayonets on them. Single shot I can see why they wanted bayonets.
With a Glock an extra magazine has more range to keep the bad guys from getting up close and personal.