Just an anecdote, take it for what its worth: when I was in college (dating myself here) a buddy of mine upgraded his "big red" Trek 970 mtn bike with clipless pedals. Several months later, he got himself a Rock Shox Mag 21. Because I was looking to upgrade my bike, but only had money to afford either clipless pedals/shoes OR front suspension, I asked him which he thought was a better upgrade. No hesitation, he said the clipless pedals.

BTW, aren't most of those track riders clipped AND strapped in? That is what I understand is common, though I honestly can't tell from those photos. I may be wrong on that.

Also, as someone may have noted above, the trackies' straps are much tighter than you would ordinarily run, if you ever want to tae your foot out at a stoplight, etc. I actually find clipless easier to get out of than anything other than the very loosest clip/strap setup.