If you have a seminar-like class with a different lecturer every week, then, yes, it's a problem if they can't get consistent notation. I'd hope that's rare in undergraduate courses, though.
And meaningful variable names would be absolutely horrible for anyone trying to calculate with them or visually comprehend them. Energy = lorentzFactor * restMass * speedOfLight^2? You'd be writing all day to get anything done, and it would be hard to see the forest for the trees.
See also the brevity of notation in J, q, and APL, and the "tacit" style of J and "point-free" style of Haskell.