There is always a danger of using circuit breakers to simulate failures, as pulling the CB on say, an attitude gyro will automatically disconnect the gyro from the display or autopilot, because the 'power to gyro valid' signal says there is no power. This is a lot different from a gyro which is getting power but sending stupid information to the autopilot or display - how do you know it is going to ignore invalid information?
So, be careful pulling circuit breakers - the real failure can be something different!