Good ol misclick when trying to click reply. /sigh
No it's not a bad idea to get her and max her if you use light and not a cash player. If you bothered to look at wiki you should know that Phoenix is the best for an all light team for a very long time. There's a 70~90% light boost eidolon that requires you use 3 different element himes but it's questionable whether or not to even use it.
If you're not using light, then obviously you can just ignore Pheonix.
edit: removed some incorrect date/info