You can use any glue you think will work. However........

Canopy glue is great stuff and worth using for a number of reasons.
It's about the best and easiest to use of all the glues. Epoxy is messy and is not easy to apply without it smearing something up. And once it's cured repairs are tough. And did I mention that it's not easy to apply cleanly.

Canopy glue can be put on in about any amount. When it dries it's as clear as the canopy so it's not going to screw up the canopy. And "too much" just turns clear and is almost invisible. And I usually put too much on, on purpose. Whatever squishes out is dead easy to wipe off with a wet paper towel. Try that with epoxy. OK, you can wipe epoxy off with alcohol. But it doesn't wipe without a battle, and leave any behind? and not get any on your hands (and you're always going to touch the airplane if you get any on your hand) Hey.... canopy glue

Dead easy to use and............

You actually can remove a canopy that's been glued on with canopy glue. It ain't easy 'cause the glue holds good, but you're not going to have to grind it off and it's not going to guarantee a worthless canopy in pieces like ones epoxied on.

Does it make a difference? Yeah
And the differences are worth all the $3 or $4 the canopy glue costs.