Couple follow-up comments: My watch can't be a barometer and altimiter at the same time, I have to switch between the modes so leave it on altimeter except when in camp. I don't know whether this applies to other models, but thought I'd mention it. I set the altimeter to a known elevation, daily, to accommodate barometric drift.

Look for temperature compensation. Without it, temp affects alti/baro readings, including heat from the wrist--very unhelpful.

Altitude can be a very helpful nav aid, especially when off trail or in the snow. It's a good complement to map and compass, especially when there's no view of prominent geographic features (most of the time when not above treeline).

Cheers,