They were designed for swamps, where apparently this tyre design works well. On snow, treadless tyres are essentially useless, and this was a large part of why

They were designed for swamps, where apparently this tyre design works well. On snow, treadless tyres are essentially useless, and this was a large part of why the cruiser failed to achieve much of anything. I suspect that at the time producing and transporting suitable tyres was extremely difficult, so they weren't able to try swapping the original tyres for something more suited to the conditions.