Fusing and in-account movement

Would be necessary if your alchemist is not your silent crusader, for example.
You buy the pendants on the crusader, move to alchemist to fuse, and move to whatever char needs it if the fusion came out good.

Sounds like more trouble than it is worth. It is way too easy to just take up alchemy on the character for the duration of the project. The only reason not to would be if you are a smith and have android heart recipes learned.
Alchemy is the best job for a main anyway due to the use 2 buff potions thingy.