The problem with irisviel is the competition, who are free as well. She's a healer who gives team guts (which is not that valuable anyway because hers is only 1k revive) but asclepius is leagues better at that, he gives way more healing and has great utility on top of that. He's not that hard to get either, if you can afford some rolls on white day.
And if we bring up her team np dmg up, well, there is a servant who heals the team and has dmg ups for the team as well, hans, who offers signifanctly more value than her overall.
Basically, she offers too little for her cost, and other very accessible servants are better at what she does.
Irisviel, for all her flaws compared to a newer 3* servant, does have one advantage at this point. You don't need to wait for a rate up or try the Story Banner and hope. You just spend some Leaves on her.
There WAS one CQ where she was a dealbreaker. Nowadays she's more nice to have.
The CQ is the Arash one from Nero Fest, right? You can even just run Double Mash + Boudica, and you'll be fine.
If I remembered right, having all 3 Servants with the Guts status is the most effective way to survive the Verg Avesta.
Ok, I forgot that one ;-)
Then there at least two:
I was talking about the Assassin one, where they killed their killer in return.
Oh, that one is even easier. That quest is also one of the reason why people use Asclepius, not Iri.
It was the King Hassan CQ from NeroFest where he was bugged on NA. He was supposed to attack the servant in the first slot, but instead he attacked anyone. And he had a super high death chance effect on normal attacks.
That quest started off bugged in JP, but they fixed it. After the fix you'd toss in a servant with a really low death rate to eat those attacks, like BB. NA got the bugged version without it ever getting fixed, and the solution was teamwide guts up pretty much constantly. At the time I think it was only Irisviel that could do it.
Yikes, so many words just to say "No".
Ouch.
What do you think?