Lew, I would hazard a guess that people using the gold maps are often people who keep their boat in the water and no matter where you live in Canada, the section you buy covers one heck of a lot of water. The hotmaps could be seen as being less usful in that for example, if you live in Alberta, there are only 4 AB lakes on the chip...not too cost effective for an Albertan. So it has to be sold a little cheaper to make people buy them. This is the number of lakes on the Canada hotmaps by Province:
AB=4
BC=203
MB=1
NB=4
NS=3
ON=80
QC=125
SK=4
and there is also, on that same chip, one lake in Vermont and 2 New York lakes.
Does that make sense?
So, for the folks of BC, ON and QC the maps are a little more worthwhile.