Yes, she's in my deck right now , and here's why:
1. Great bluff. With a 9-damage potential, people are going to put at least 4 pills against her or waste an SOA.
2. Fury her and she deals 11 damage. With the DR ability of the other pussycats, sometimes that's all you need to win the match.
When you play against Pussycats, there are less abilities you have to worry about. So I wouldn't say that the SoA would be wasted against Muze.
But yeah, I would include her too. She is a good enough 3*. She will imho lose out against most staple clans and SoA, but she is still better than any other 3* Pussycat. At least she has the potential to draw pillz from the opponent. Which isn't a bad thing.