At a 15 minutes of flight it's being generous to call it a toy as that isn't even enough to justify going to your flight area, going through your pre-flight checks and everything else that needs to be done and I doubt you're going to be swapping out the batteries in a matter of moments. it's still not the most unsafe looking concept I've seen, it's an octo-copter so if it's designed with any safety considerations at all it should be able to operate with one motor out of action.