Well, of course, as EDC (everyday carry) items it would depend on your local and state regulations. But in SHTF, they all make great ad hoc spear tips for defense and hunting. I'd keep them in good condition and ready to deploy if the shizzy hits the fizzy.

Assuming you have the propper lug/barrel combination they could be great for intimidation, give you a little bigger "bubble" around you, crowd control factors, urban CQB SHTF scenarios, or running outta ammo. They are also just fun to have around interesting collectibles.

Nice bayonets, well they're made for combat because they have a double edge. You could use them as a survival knife or a beater woods knife. I would personally save them for the cool factor and just keep them as a display knife.