Not really and difference in terms of efficiency. However, read the paragraph in the original post about Rule Machine concerning how it evaluates the rule.
At this point there is no extension of Rule Machine into integrations (Harmony, Hue, Echo, etc.). It supports core ST capabilities.
This is well beyond the original intended scope of Rule Machine. Timers can be very tricky, and I maintain that they are best implemented in an app that has some context, which Rule Machine does not. I will look at enhanced timer functionality.
If effect, it already does this. The app subscribes to the events of a switch that is a condition. When the rule evaluates, obviously it looks at the state of the switch. Due to the subscription, when the switch is turned on or off, that triggers an evaluation, which discovers the state of the switch, and if the rule truth changed, caused the actions.