I think Nigel's point about visability vs low cloud is valid. The problem is that you rarely know what the weather is going to do, especially in the hills. Moreover, given the versitility of helicopters, there will always be missions where you will not know whether the weather is going to allow you to get to your destination VFR.
Nigel's local knowledge allows him to decide if he can get over the last hill before home. True, flying below a low (300' say) cloud base in 9999s is bound to be easier than if the cloud base is say 700' with 3000m vis. But local knowledge is just that. We all have it. But what I'm happy to do around my home base, doesn't mean to say I can safely fly in the same conditions somewhere new.
I would also be very careful assuming that flying low over a ridge line is "not in itself dangerous". There be dragons.