Whilst the OP later explains he is referring to a skid helicopter, there are multiple scenarios which could dictate either option.
A skid machine generally has plates under the skid to allow for running along a sealed surface, which can (& does!) leave significant surface damage to a runway seal. Does the emergency landing warrant this?
How large is the helicopter, what is the emergency, how far is it likely to slide? Shortest run-on is likely to be a limited power approach, eg single engine failure on a multi. Longest; maybe a tail rotor failure of some sort. For a short run on then take a firm and level grass and leave the runway clear. Longer run for a T/R failure make a judgement call, but I'd lean toward a runway as a more forgiving surface to an off-centre touchdown.
Then there are the wheeled machines and their foibles, most of which would dictate a better sealed surface.
But as already mentioned, that seal doesn't have to be a runway. It could just as easily be a taxiway or even a clear parking area, especially if there is a significant crosswind on the only available runway. The same holds true of a skid run-on landing on grass, lessening the crosswind issues of going for a seal.
Since the OP is from India there could be further considerations dictated by local norms and requirements?!
Edit to add: never, ever, let the considerations of other operations influence a safety call in an emergency. It should be of no consideration that other serviceable aircraft may need to divert when assessing the safest way of getting yourself and your crew or passengers away from the landed aircraft in one piece.