ZeroZet has a point. For Adele to pass Yuyu in damage, she needs to have skill active. Yuyu has higher attack outside skill AND slight Attack Speed advantage, along with lower cost and ability to increase range if needed. Generally you're not using Witches (besides Despara) for burst damage, you're using them for early magic damage + Slow effect. For that purpose, Yuyu is simply better. Also, Adele, being a platinum unit, does not have instant skill available. Her skill has 12.5 sec initial, 25 sec re-use at max skill level, with 45 second duration. This means for 45 seconds, assuming you actually HAVE her out for a full minute AND have her skill maxed, she will have more damage output than Yuyu. Without skill her damage advantage decreases due to longer skill initial and shorter duration, and that's still utilizing multiple assumptions that do not apply to some players.

I utilize Adele simply due to the ALL HP UP buff, if UP early on is tighter, she's getting swapped for Yuyu, hands-down. Minimum of 2 less cost, and she's more likely to be CR'd due to being gold instead of platinum, and outside of skill she has more bang for the buck.