Yep, it's to get more plants from each seed potato.

EG

- Can I just plant them as they are without cutting them in pieces?
Certainly you can. In fact, if you don't have time to let the cuts 'heal', you'd be better off.

I planted whole potatoes this year, just because I was late getting them in and I didn't have time to let cut ones dry a while. I purposely bought the smallest seed potatoes I could find in the bin. Normally I would buy larger ones and cut them in chunks with at least two good eyes in each, then lay them out to dry for a few days before planting them.

Granny

Here is a link that might be useful: Annie's Kitchen Garden

I think next year, I'm going to aim for smaller seed potatoes and not cut them. I tried chitting them, and the uncut ones looked in much better shape when I planted them out. The cut ones were getting pretty dry.

Here is a link that might be useful: Tales of a Transplanted Gardener