I may have a unique perspective.

I rode a great deal in the 70s and 80s. By the earlier 80s I was using toe clips. Left one tight, right one just loose enough to slip out.

Then came marriage, three kids, divorce and a few extra pounds later (ok more than a few). Two years back bought a hybrid, MTB style pedals. It was ok, but I knew if I wanted to be smoother and ride longer, I'd want clipless.

Bought a road bike this year, first long ride and on platform pedals. Hated it. Foot kept slipping when I was trying to find the right position. My shins didn't get hit, but I did lose some momentum a few times, especially when I was tired near the end.

Bought clipless pedals and MTB shoes with SPD cleats. Adjusted them before mounting to the bike. Took a really long ride, got out of clips at every stop sign. Now it feels natural. Haven't fallen yet (had fallen in toe clips before though),

And as to why have them at all, I find high cadence spinning smoother and easier when firmly attached, and I feel it works better when climbing.