I had full kindergarten with recess and naps. We didn't do the cot thing but it definitely helped us. I know i would have been in the corner sleep somewhere if they didn't. And I went to a kindy class that had homework (writing letters , numbers, words) so even though we played, we did work (more than what some of my friends did @ the time) and we needed the nap!
It has been my personal mission to get 45 min nap time incorporated into the work day. Every job i have been in I have asked that. Yeah they look at me like I am nuts but they wish for it too