A boat's use is inversely proportional to her length".

That may be true for some but not all. Usage depends more on the owner
than anything else: How much do they and their family enjoy boating;
How well suited to their favorite use is the boat; How convenient is
it to take it out; How much free time do they have, etc?

I know people who buy a boat and then find out they don't both enjoy
it, or the boat they bought is not right for its intended us. Both of
those factors are more important than size.

It is also true that no one boat is right for all purposes. We use the
GB49 for cruising, both weekend and long range. If I just want to go
for a quick spin however, I'll take out the 24. Both boats are equally
convenient to take out, but one is built for size and comfort, the
other for speed and shallow draft. It is easier to single hand the 24
and that's also a consideration, but not the primary factor.