Quite a few people on the s2 forum who have driven for a decade or two using the grease in their swivels.
That is not evidence that the grease on it's own is as good as grease & a splash of EP90, that is just a fact that you and other S2 owners have ran with grease only in their swivels for a decade or two. There is no evidence here on a set of like vehicles, driven in similar circumstances that either way is better or worse and it would be difficult to prove.
I've never said that the grease doesn't work, I said originally 'Also, when you are done it's a good idea to add a splash of EP90 - the grease is good, but it's fails to splash lubricate the top bearing.' you called it out and I said 'The grease is probably fine, but I am a firm believer that, as I said, it's a good idea... '.
Do you put a smear of engine oil on oil filter O-rings or spin on fuel filters before you fit them, do you copper slip nuts and bolts, on a can type oil filter do you pour some oil into it before fitting it? This type of list goes on, but none of the aforementioned steps are critical to the task however they are all a good idea and if something is a good idea it's usually worth doing.
I've run grease with a splash of oil in my Defender swivels for about a decade now and have had no issues, I ran only EP90 in my 300tdi Disco for 146,000 miles and never had to change the swivel bearings, CV's etc. It's going to be a hard one to prove one way or another when a third argument is that EP90 does a perfectly good job itself.
All I am saying is, I believe, as do many others, it's a good idea to add a splash of EP90 in on top of the grease.