I use unwanted 3-star CEs as resources to build up my 2-star CE bombs. These are CEs that aren’t useful, replaced by something better, the event is has already rerun, or it’s a mix-stat CE that doesn’t even give starting NP.
Yes. Wait for the next download campaign (or whatever).
Mana Prisms just ain’t worth it, unless you have serious issues.
What Recks said.
Since there is no way to raise CE levels outside of feeding them other CEs (and special EXP fodders being rare), provided you don’t desperately need a stack of MPs, use the otherwise useless higher rarity CEs for levelling as well.
Cool, thanks. That’s what I was thinking and needed confirmation.
On reruns when I don’t need the shop CE, if I’m not burned out farming everything else I’ll often still buy it just for the exp. If you don’t have millions of FPs to spare, then every source of exp is to be used.
What everyone said. To some people who have maxed out all their best servants, the most valuable resource from lottery events is actually the FP, because trying to max out every useful CE is the true final boss of this game. You’ll eventually get more MP than you’ll ever need from events and burning duplicate silver servants (and eventually silver XP).
I don’t know, when those limited shop CEs come around for 5k MPs each, it can take a big chunk out of one’s stockpile. I haven’t even bought Mona Lisa yet, even though I have enough, because I’m worried I won’t have enough for Bella when it drops.
Very true, MP can be problematic especially if you have your collector streak going with the limited CEs and want to catch 'em all. I suspect the average player falls well short of a hundred boxes per lotto, after all, in which case it’s quite possible they’d end up prism-strapped.
(and eventually silver XP).
And eventually 4* EXP as well 
those lotto EXP pyres still haunt me.
Fair enough, though I don’t want to believe my >50K MP are from lotteries alone…
Anyway, my point is that there are several other sources for MP, but not CE XP, so burning gold CEs for a few MP isn’t worth it, imo.
