Endgame says:

Rena isn’t special anymore.

Like huge boobs? Rose beats her out. Ara isn’t that much smaller and is much cuter. The artwork of Lu before the incident makes her look even bigger as well even though we’re not getting that in the game proper. But still.

Like pointy ears? Lu has them too.

Like immortal women who won’t wrinkle until long after you’re dead? Lu is suggested to be thousands of years old while Rena is only suggested to be hundreds.

Like domineering personalities? Come on. Lu is a demon queen. She can probably do it much more seductively compared to Rena’s blunt style of shouting you into obedience. (Hopefully. I mean, we have no reference as to how Adult Lu acts and Loli Lu is certainly bratty.) BR Ara is probably a better domme type than Rena too.

Want a lady that’s close to nature? Artea does it better.

Like the hair color? Artea has it too.

Hell, even Raven just wants her because she happens to look like Seris…..