+1.

Not to mention - do you know what you would use the altimeter/barometer for? Is it a function necessary to your enjoyment or your survival? If not, why are you wanting to get that item?

Lightweight backpacking means leaving things that aren't necessary - map and compass skills aren't going to leave you in the lurch since there are no batteries to fail in subfreezing temps, and no electronics to break or fail to find a satellite.

The altimeter will be of little use without the ability to read a topographic map - with skills and map, you can use the altimeter to triangulate your position with more precision than without it. Without skills you are left with... your current elevation. If it's an accurate reading. Electronics sometimes aren't accurate.