The platform may have been designed to help provide a target for clipping in, but it was pretty clear that some also used it for riding unclipped at those times they felt they were better off being unclipped. It was also clear from the discussions that others preferred to be clipped at all times regardless of the terrain.
I remember the thread from last week and maybe this is a question for the Mtn bike forum. If foot positioning is the key to remaining unclipped it seems it would be real easy to put your foot in the wrong spot and end up clipped. Maybe it's just not that big of deal when it happens. I've been debating over whether to try riding clipless in the winter which is why this piqued my interest. Being able to get a foot down quickly is what has kept me on platforms during the snowy months.
I know. Winter is quite a ways off yet.