How many wishes do you have?

If you can use Koko Donut, go for EL. Otherwise, the possibility of ending up with 2 is too much of a risk. And it'll literally be unusable on anyone but Kokomi/DPS Barbara (copium). I'd say go for it even if you could put the 4 stars to good use (not really, cause again double Donut).

Otherwise, be smart, get your cons, the weapon will come back sooner than we expect. Plus, Raiden's banner is very good this time around. Do you have Benny C5 and Sara C6? What are the chances they'll be on the banner next time? Consider this, people went for the Jade Cutter last time on Donut banner, next time around, it was on the same banner as Kagura's Verity. It's your primos and you can do with them as you please, but if you have enough for C2, cross your heart and wait for the next time EL comes back. You could end up wasting a guaranteed Kazuha on 5 star fodder. The Unforged was still usable, Koko Donut is a downgrade to a free 4 star craftable.