That's true, I know I've pulled my feet out of look pedals before. I tend to find though that I can easily fall out of straps too. I have them loose enough to make it easy enough to get feet in and out quickly, but then if you're not careful they can come out accidentally.

I think the reason though that most people ride clips and straps are because they ride in the city and want to be able to walk about in normal shoes too when they've got wherever they're going on their bikes. I know you can get shoes with recessed cleats (although certainly for me you can't, try getting them in a size 49/50) but mainly they're too stiff or just don't look cool.