EKs can't use an Arcane Focus. They need a component pouch. Same with AT. And I think Ranger too, but may be recalling that incorrectly.
But yes, a S&B/TWF EK or Valor Bard needs to pay attention to what spell components their spells have, even with Warcaster. But it opens up a lot of Spell options.
It's also useful for Clerics/Paladins that want to cast V/S spells with their hands full, since they can't do that even with a Holy Symbol inscribed shield. V/S includes Cure Wounds, and various other spells.
Or Just use a 2-handed weapon. (My personal preference for EKs and Valor Bards.) Or just put the weapon away with their free object interaction, which effectively just means giving up your OA this round for S&B, although not TWF.
Warcaster's huge benefit is advantage on Concentration checks. The OA with a spell is nice too for non-melee. The S-component with hands full is somewhat niche.
I thought you explained it very well before, it is a "feat tax" and it must be paid. And you get goodies with it.