Does it matter? The average C6 cost for a 5* is ~1500$ (pity, random early 5* etc. all included)
Half that and then some more and you are still at 500-600$.
Either way, it doesn't change the fact that Eula is not hitting that "casually" without a 5* weapon and C6.
But I don't see a "casual" Ayaka hitting anywhere close to a "casual" Eula. Neither DPS wise nor burst-damage wise.
But I don't own her. I just don't see it in her kit.
Ayakas burst was absolutely horrible to use in the try out due to auto targeting.
And her cryo infusion and how to get it is probably the worst part of her gameplayloop.