Some servants they make a noticeable difference. Star gather on high-return Arts cards, debuff-clearing, heals, crit-boosts…
They don’t matter so much for most loopers, but for anybody who uses face cards they’re excellent if applied correctly.
Arjuna Alter without command codes is noticeably less effective than he could be. He’s obviously still strong if everything lands, but if they resist his buster down debuff you have to live knowing you accidentally borrowed the AA that doesn’t have debuffs on his command codes and you just gave away potentially hundreds of thousands of damage.
I’d rather borrow an NP2 with a few debuff command codes than an NP5 without. It’s weird to see an NP5 100 2k/2k AA without ANY command codes, but my list has at least one of them still.