Totally disagree. This is a common misconception by those who don't understand what bearing buddies actually do.
Bearing buddies are designed to keep a constant, low-pressure reserve of grease pressed against the bearings. This provides for a slow movement of fresh grease from the outside bearing to the inside bearings.
With plain grease caps, even ones with zerk fittings, you will never be able to reliably force fresh grease all the way through the hub and into the inside bearing. Bearing buddies are constantly repacking your bearings with fresh grease.
If you think bearing buddies are "messy", it's most likely that it isn't the bearing buddies at all. It's the fact that your rear seals are shot. Probably due to a lack of grease.
Yes, some grease does get forced out the back seal. There is no such thing as a totally tight rotating seal. I'm more than willing to put up with a little grease spatter because I know that means that the fresh grease is getting through to the inside bearings and it's displacing all that gritty, dry, and polluted grease.
With several fishing trips to Canada every year, I rack up thousands of miles on my trailers every year and I've never had a bearing issue. I may go through more grease than is strictly necessary, but I believe when it comes to grease that more fresh grease is NEVER a bad idea.
Grouse