Well, in a nutshell, it'll probably work out like this:
  • Animus relic on one of your jobs, your "main" which you use for statics in the hardest content (your Soldiery tomes should probably also be going primarily into this job).
  • Eventually get upgraded Masterwork, Leviathan, and High Allagan weapons for other jobs.
  • The developers alter the requirements for building Animus relics at a later date and/or Myth drop rate, making the Atma farming and tome purchases much quicker to get over with.
  • Now you can go get Animus relics for other jobs.