Even in fantasy settings I tend to try to keep a scientific approach to things. I do not like the concept of omni-potent beings, so I always have some form of stats for ever being, even gods.
True, some of the gods are incredibly powerful and virtually impossible to even scratch by players, but in order to fit into a gaming system, like RM, I feel the need to keep things within the limits of the rules. A lvl 500+ entity with various overpowered inate abilities perhaps, but they would still have stats.
Will players ever meet those entities ? Highly doubtful. They would usuallt meet an avatar, but in the rare occasion that they face the real deal, they would not stand a chance.
Having said this, I also have gods that are way lower level. I even have a god that's only lvl 20. His powers are not as crazy as some of the bigger guys but his influence is plenty for him to do what is needed, and the players will never meet him face to face anyways so the level not really important.
The main problem with giving stats to everything is that everything is "killable". Without stats you can do whatever you like but once you give them stats people have a chance, so it all comes down to whether or not you want that. And there's a difference between not having stats, and just not having them written down yet