pen is the ultimate tool for taking notes.
laptop lacks free drawing tools (combined to keyboard noting, free software, for many operating systems, _small_, preferable portable...)
but if you can video the whole stuff then you can freely concentrate on the lecture and if you want, use pen from time to time for clarification.

laptop is limited to technology, in one or more ways and to your abilities to use it.
pen is limited to you. only.

no. and yes.

two magnetic elements. reading:
0) same direction = 0
1) opposite direction =1

they do not have 00, 01, 10 and 11 states, which would be four states.

elements are read in an "old-fashioned" way, they probably _could_ be read in all four states, but they are not.