You're comparing a gold unit to two plat units which are great even by premium plat unit standards. Also, not everyone has a necromancer (OP for example doesn't). Even if you do, having a fairly cheap unit that deals comparable DPS to a gold archer with tokens would still open up more tactical possibilities. I'm not saying she's a priority to level especially when you have Bashira (a unit that will most likely be the MVP for a new player for quite some time unless they get a strong black), but I don't see how she's useless either.