Even if the avatar didn't get amazingly good paths, it's still quite usable as an SC. Though ushabti avatars do annoyingly have the does not heal tag, making it somewhat problematic to use them.
Go for it
Like I've said before, some of the randoms on tomb kings are just so random it's hard to decide what to do with them. It seems to me like they are either thugs, forgers, or army buffers depending on their paths. Sorcerers and high priests can handle just about all the battle magic you really need.