I would agree with Leigh Palmer. Do not teach about significant figures in
an introductory course. It is information-overload and does nothing to
stimulate interest in the subject.
In my opinion, information-overload also applies to other material. In
electricity and magnetism, for example, why do we bother to teach about
capacitors in series and in parallel? The proofs of the basic "theorems"
on this are done incorrectly in the texts. In addition, the students just
memorize a prescription and do not understand what it means.
If material is not interesting or significant, we should question if it
should be taught. Students who need to learn such material can later get
it in a more advanced course.