In Tasha’s Cauldron (and the preceding Unearthed Arcana), the feat Eldritch Adept grants one Eldritch Invocation, with a prerequisite of Spellcasting or Pact Magic. Hence, it excludes only non-EK Fighters, non-AT Rogues, Barbarians, and Monks.
I understand the thematic reasons for this prerequisite to exist, but are there game balance reasons for it? Answers should include example class/invocation synergies.