Somebody was in the news the other day because their clever country-code TLD was taken away by the registry. All of the country code TLDs have weird restrictions with which you can easily fail to comply. Recourse for smaller registries can be harder to obtain.

In this case I'm not sure why they went with 'sleepio' if they weren't going to use '.io' other than perhaps it's trendy right now, but I think they probably made the right move getting the .com.