Produce is better stored in sand than a cool dry refrigerator?

In Ireland I chatted to a green grocer about the merits of muddy potatoes. The potatoes are sold completely unwashed, each with a healthy coating of mud - and in the bag, they will put an extra scoop of mud - "keeps them fresh longer, so they say".

Potatoes makes sense -- you shouldn't refrigerate them as part of storage.

But I always thought I wanted to refrigerate carrots and scallions.

Is keeping them in dirt better than refrigerating them?