But pronunciation is very variable, even living languages have multiple different pronunciations in use at any given time (a.k.a. accents) and for a language like Latin that has been in use for thousands of years, the possibilities are endless.

Being able to establish one-to-one correspondences between Latin words and their descendants in modern languages can be helpful, but it doesn't matter much whether you're using the "correct" Latin pronunciation, so long as whatever pronunciation you do use maintains those correspondences.