In the shows and movies taking place post-TNG, we see so many different phaser rifles! DS9 continues to use the type-III introduced in TNG, while VOY busts out the compression rifles in "Caretaker." Then, we see no fewer than three different kinds of rifles in ST:FC, one of which goes on to be featured in VOY, swapping out with the compression rifles. Why so many rifles? Why didn't VOY just use the type-III from TNG and DS9? Did they each have a different function?