Yup, more music for your orchestrion(or to sell) is nice. Carpenters make the scrolls they go on, alchemists make the ink and the actual music roll. Several classes(LTW and ARM especially) make extra bardings so you have more options for dressing up your chocobo(or to sell). Several classes(WVR has the most) make extra minions you can summon(or sell). Every class(even CUL) has at least a couple furniture-type items they can make for house decorating. If you look through all the lists, there are fun or useful recipes for each class. One thing to keep in mind with melding in particular though is that you can only meld things for the classes you have leveled up. A level 70 GSM(who in this instance somehow didnt level anything else) can meld any GSM items, but they cant meld even level 15 blacksmith items. So this is another case where leveling multiple classes makes it easier on you. When it comes time to actually meld something the game just checks if you have the right class at the right level, so you wont need to actively swap when the time comes.