I do think they're useful.
Imagine a watch with an old-syle blued hairspring. You'd have to be careful around fridge magnets! So the greatly increased non-magnetic qualities are definitely an advantage.
But there are limits. In all these specifications or claims (1000 Gauss), there are limits that are beyond the capabilities of the materials and the design. I am sure you could make a extremely non-magnetic watch, but would you wear a half-kilogram chunk of soft iron on your wrist (Panerai fans excepted
).
So the question is - I can't answer this without detailed research and comparison - are watches that proclaim high levels of anti-magnetism really at the optimal level given then constraints of size, weight and acceptance?
The real question is: could they do better? I am inclined to think that in the case of the original Milgauss, which was created for this purpose, probably not.
In the case of modern watches, also probably not, but advances in materials should make this a possibility. Subject again, to the limitations above.
All of course, my opinion only, would love to hear others,,,,
This message has been edited by BDLJ on 2009-10-13 03:43:14