The old modern architechture saying "Form follows function" can be adapted: Pool lining follows shape and function. If vinyl won't do the job well, use gunite and don't worry about it.

If vinyl works and you're happy with it, use vinyl and don't worry about it.

It's not that one is "better" than the other, it's that applications are different and one or the other will be more appropriate.

Just be sure you have ALL the variables.