Welcome on NP
There are for for better domain names available in rocks extension, and these you mentioned will not attract any body. Good Luck though
let me share my experiment with one of rocks domain;
I bought some rocks domains, one was really a premium one and it was a three letter word, I just bought only to make it a try and I was able to sell it on my first try, I sold it a little higher than a reg fee though.
So my experiment says never to buy a rock domain.
btw i still have following domains and these would have been premium had it been some good extension;
editor.rocks
ged.rocks
webcam.rocks
jets.rocks
favorite.rocks
Estibot gives these domain really a good value, but still these are not on that level i guess.