Clipless systems are tangentially related to increases in efficiency (and in a sport of marginal gains, even small increases are worthwhile). To wit, G. Mornieux, B. Stapelfeldt, A. Gollhofer, and A. Belli found in 2008 that shoe-pedal interface systems were essentially identical in terms of efficiency at all submaximal efforts; clipless systems were more efficient at maximal efforts.

Clipless pedals are more intimately related to improving bike handling by anchoring foot location on the pedal during stroke. It operates on the same principle as suspension--being in contact with the surface improves control. This is something that is difficult to measure in a lab but which is noticeable for experienced riders ("feedback" is the usual catch-all for this measure).

I'm downvoting you because you present yourself as being unreasonable despite a wealth of other redditors explaining that experienced riders (myself included) have no trouble disengaging a clipless system in an emergency.