Does a low page limit (3 pages) indicate anything about the quality of a conference?
Do not confuse quality and quantity: the two dimensions are orthogonal.

A 3-page limit means that the conference is really asking for extended abstracts, rather than full papers.  You can't say much in a 3-page extended abstract, even in the highly dense IEEE two-column format, so it can't be treated the same as a full paper, but that's not reason for it to be bad, just terse.  The conference might well attract very high quality 3-page extended abstracts.  One thing that some such conferences do is have an associated journal special issue, where full papers are later invited.