Carnauba wax isn't a normal finishing option for guitars. Whilst it is one of the hardest of waxes, it is still a wax and will be softer than other finish options. I'd definitely try it out on scrap wood first. Once you put it on, I'd imagine it would be very hard to remove to apply a different finish, and being a wax, I don't think many finishes would stick to it if applied on top.

It will probably need regular maintenance. From pictures of it in natural form, it looks yellow in any quantity, so will almost certainly tint the finish, and any deep pores in the grain may look light yellow due to an increased thickness of the wax. So it may work well on nice flat and fine-grained maple, but not be so good on mahogany or ash.

But until you try these things you don't know for sure. I'd suggest testing on some some scrap wood and see what you think. It shouldn't take too long to apply.