Well, while you can't raygun the maids after they get hired at Fantasy Fusion, you can at least zap them when you have the initial random encounters with them while out exploring just like all the other NPCs...
Yeah, since it's basically an extra/cheat given how much it costs, it'd certainly be nice to be able to use it on more than just the random NPC encounters. Thankfully there is at least the legendary sandwich late game that you can give to basically everyone in the game in order to make them permanently bigger, unlike the raygun only being temporary.