Bearing Buddies on a caravan

I'm currently looking to buy a van, most likely a 2004 Jayco 18' Freedom Pop Top.

My question is this: can Bearing Buddies (which they use on boats (to pump in fresh grease) be fitted to van axels to help prevent bearing wear? I'm thinking that the occasional pump whilst on trips may be beneficial but I haven't heard of anybody using them.

Ian, SA