One word name might go well for this extension.
It's still in its infancy and predicting price would be more of a guesswork.
However, if you see, since the names are available for registration, companies would want to go for one word names like Banking.app etc.
Since CoreBanking.net sold for $3,650 a year back, this could have some value. If it sells, it'd be xxxx or doesn't sell at all.
You'd have to see how the sales go for this extension.