The purpose of a reality check is just to increase your awareness in general, and then to serve as a tool to help you actually test it. Yes, sometimes you will randomly RC and will become lucid from that. Other times, if your awareness is good enough, you'll certainly just realize you're dreaming without even having to bother with formalities or questions. You just KNOW. Sometimes this happens, and you foster a little doubt so you do a RC to help convince yourself and build confidence. Either way, RCing is fantastic for stabilizing a dream and your lucidity. So, congrats on the spontaneous lucid