This came up on a recent thread, and I said (just my opinion on this, by the way, and to each their own heart) ...
It's just one of the many trappings that can be removed from zen to bring it up to date.
I feel that the use of robes is an individual decision. Personally, I am happy in my ordinary clothes when sitting. For me, there is then no real separation
Last night I was having a discussion with a friend about zazen and my local zendo here in Madrid. He's interested in checking out
"I am but mad north-north-west. When the wind is southerly, I know a hawk from a handsaw."