I think it's because 80mm makes for a reasonable wide field scope.

That said, I don't exactly disagree with you. An 80mm scope is really in the
toy category for intermediate and avid amateurs. It's a play thing.
Something you take along on the family trip. You convince yourself that it's
for observing nature, but deep down in your heart you know it's just a
pacifier for when you start jones'ing for the scope you would have brought,
if you hadn't brought the family. g

Personally I don't think an 80 mm scope is a toy at all.

When I go stargazing in the mountains I almost always take two scopes, one
70mm-80mm and one 8 inches or larger.

Small scopes like the ED-80 or the Pronto do things that larger scopes cannot
do.

It is certainly true that a small scope is good for viewing nature, I have a
thousands of images of birds to prove that point. I alway keep a small scope
setup ready to shoot/view an interesting bird passing through.

But they are also good because they do those things that a larger scope cannot
do, widefield views, from 10x-30x or more. 5 degree swaths of the sky provide a
different perspective and are just not available in the 10 inch DOB or and 5
inch MAK.

Another advantage of a small scope is that it can be built in a way that would
be unaffordable were the scope larger.

So small is good for somethings. When small is good, one can mistakenly get
tangled with Aperture fever and wish an 80mm were a 90mm when in fact an 80
will also do things that a 90mm will not do. 25% increase in light gathering
and 12% increase in resolution is not such a big deal, certainly no one is
trading in 8 inch DOBs for 9 inchers....

Of course in the case of the ED80, making it an APO was of paramount
importance, making it affordable was of paramount importance, and keeping
reasonably sized was important as well.

The cost would have increased significantly, the focal ratio, for the same
color correction would have increased from 7.5 to 8.5 and OTA would have grown
from a passable 24 inches to a now not a spotter at all 30 inches..

Someone one commented that appreciating the views in a small scope was
something that was more often the province of experienced observers who had the
observing skills to make the most of the subtleties of the small aperture. To
me, that made sense.

In my development I have certainly found this to be true, targets that were
once difficult from a dark sky are now doable from a light polluted sky in a
small scope.

jon