Old-school spools with open edges, like this picture, were a problem; they left cardboard dust and crud everywhere.
Newer ones, that most manufacturers (e.g polymaker, overture, esun, elegoo, just about everyone) have gone to, are fine as long as they’re not bent. They don’t shed dust and crud. They normally only need printed guards if they’re bent or too slick for the AMS rollers.
Sometimes cardboard spools of either type are too light and have issues at the end of the spool. Popular ways to add weight include using a spool-center desiccant holder or a throwing a 2" steel ball bearing into the spool, or respooling to a Bambu or other non-cardboard spool.