Yeah, at a glance it doesn't seem like SSR Bastet is anything special. She's not bad, just not the broken level we can expect from the best of Hime. Her greatest asset seems to be the fairly impressive +10% HP +5% Assault from the backrow, that's almost like adding an extra SSR weapon to your Grid (with the base Atk of 0).

If SSR Bastet is great, then it'll all be because of her Counterattack buff. Without data on how good that is at low HP, it's impossible to say. Maybe the DMM wiki has been updated for that, but I can't be arsed to check since I don't have much hope for her.