Elytras are hard to come by, and even harder to be made useful through its very limited durability, to the point where I'd be more disappointed getting it from a legendary crate than a random potion. And what makes this increasingly worse is that once you have used the elytra presumably twice, there is the realisation that its not a viable mode of transport, instead taking the role of more a trophy piece. I recommend still prohibiting elytra enchantments, but instead provide the ability to repair one, whether that's through some kind of NPC in spawn in exchange for currency, or a shop- keeper that sells phantom membranes.