Foot shifting while pedalling
Clipless pedals are a matter of preference - you don't have to use them. There are alternatives such as "half clips" which might suit you better. 

I've come to like mine, with mtb shoes and pedals that are designed to be rideable with clipless or normal shoes on either side. These allow you to ride in an alternative position (with the pedal under the arch of your foot if getting ready to stop, for example). It's often wet here and feet sliding around on the pedals can be a real nuisance. But since buying my clipless pedals &amp; shoes I've also bought a pair of pedals with much better grip against the soles than my old plastic platforms, so you don't need clipless to keep your feet from sliding