Of 13 bikes I have 1 with clipless pedals (my mtb) and when I get the new ss mtb built it too will run clipless since I ride on some pretty sketchy terrain.

The bikes with toe clips number 6... these are all road bikes or fixed gear bikes and the clips are essential with the fixed gears.

So that leaves 5 with flats or half step pedals and these are either older bikes with rat trap pedals, bmx half steps for utilitarian / winter riding, or simple flat pedals.

Finding good shoes for the clips is a bit of work as you want a shoe with firm sole for good power transfer, sturdy construction to handle the wear, and a fairly smooth sole to allow the pedal to slide in and out of the clip/strap smoothly.

This is one reason why clipless pedals are also very effective as they have extremely rigid soles to provide enough strength to hold the cleat and this also provides a better power transfer... when you are going fast and hard a little foot retention is a good thing.

I can ride pretty fast on any type of pedal and don't worry about my foot slipping off but am faster when I am clipped in or run clipless pedals... bunny hopping stuff is also easier when you are attached to your bike.