I prefer clipless in snowy conditions - snow tends to build up on soles of shoes and makes for a slippery experience. I don't want to accelerate out into traffic and have a foot slip off the pedal.
Bought my first ever pair of studded tyresfor this winter. They are usually pointless in the UK - we get snow on the roads for 3-4 days a year, and black ice in the shadows. Then the last two winters we've had heavy snow, packed to ice, for months at a time. Never really worried about riding in the snow, but the packed rutted ice defeated me last year. One crash at least every 20 miles or so was too much.