No superpower is entirely useless if you know how to use it right. That being said, Blake has no control of his ability to switch with himself at different times (I don't know if I explained that well..... pretty much when his emotions are strong, he switches bodies with a version of himself from somewhere else on his time line.). This gives him way more trouble than it's worth since he has to always keep track if when the switches happen (so he isn't somewhere dangerous when it happens, etc.)
Give me someone who you would want to go one a fantasy adventure with