One of the advantages is financial. Generally a plastic bathtub liner or insert costs hundreds of dollars more than refinishing. A second advantage is that in the event the bathtub is damaged, the repair is simple if the bahtub has been refinished. Not so with the plastic liner. Cleaning the bathtub liner with the wrong cleaner can do irrepairable harm. A reglazed tub recovers nicely! A reglazed tub doesn't get mold between it and the original tub. On many occasions water has dripped slowly or leaked between the liner and the bathtub. We have refinished bathtubs for people after they had the costly liner removed and the mold and mildew was unbelievable. We feel that reglazing the bathtub is genuinely the best way to go.