The advantage of braze-on/glue-on/rivet-on derailleur mounts is that they can be fitted to non-round tubes. The disadvantage is that they may restrict the range of chainring sizes you can use.

Clamp-on front derailleurs are more versatile in that they can be positioned where you need them, but they only work on round tubes.

If you have a round seat tube there's no compelling reason to use a braze-on/glue-on/rivet-on derailleur mount.