Originally Posted by
WalksOn2Wheels
To be slightly more specific, I think some folks like the barometric altimeters for riding because it gives decently accurate data on the fly, particularly if one is doing lots of climbing and wants to add the ascent rate data to a page. Most of us don't use this and really just want overall elevation at the end.
Barometric altimeters provide reasonably accurate data over the short term. If you stop for coffee or have a long ride there may be some errors if the atmospheric pressure changes. But all the little hills you go over should be captured fairly well with the barometric alt. GPS tends to be noisier and maps aren't always accurate for things like bridges or overpasses.