I began touring in toe clips, then migrated to SPD's for a number of years, then returned to toe clips. Among my reasons:

• It was annoying to me to have to click in and click out numerous times when riding through areas with back to back stopping. With toe clips I can either slip in or just ride on the back side of the pedal.
• The toe clips allowed riding in any make of shoe. My riding preference is a stiff soled SPD specific shoe but without installing the cleats. This gives power to the pedal when riding yet remain reasonably comfortable when walking around during the day. I carry a comfortable, lightweight pair of walking shoes for when the day's riding is over.
• On some floors, even a recessed SPD cleat still has a tapping or grinding sound as you walk around. I like to stop at museums, et al and got tired of the sound drawing attention to me as I walked around the exhibits.