At the moment GC seals can be made via two methods, running fates and GC leves. One of the main uses of seals other then equipment is the manuals that boost gathering and crafting, so if you'd like to level up a DOL/DOH profession, seals are almost a necessity.

Since, as a gatherer or crafter, leves are too important for us to waste on seals we either have to level up a new character or use an already existing level 50 to grind seals running fate. This really doesn't seem like something that was really thought out.