I put the question to my friend Ian Chisholm, a local luthier of many years of experience and a good friend who has made many excellent instruments for me. I quote his reply, form your own judgement:

Yes, I've seen those discussed on a forum. They give you Lowden style string changing while keeping the ability to pop the pins for work on the saddle or pickup. The big downside is that they're chunky brass things. Plenty of people seem to believe that brass bridge pins are good so bigger must be better. Very hard to really prove one way or the other but I strongly believe that extra weight on the bridge is a bad idea. Think fiddle mute.