IMHO:
I Loved them, I "hyped" them, and I preferred them ... (to e.g. Acer palmatum, because of easier to obtain e.t.c. ).
But in most sense I was wrong.
Fieldmapels are not that esay (to style) as I thought.
The stiffness of theire growing pattern is not easy to tame.
They are a bit affine to mildew, what is not letal but annoying.
They are very apical-dominant. Promoting the lower branch-sections are hard work .
The bark is easily sheared of, when dewiring is conducted.
You need to wire the green shoots to achive curvated branches to the twigs and branches.-
All in all,
my fifty cent to your thread-title:
easy to grwo and "forgiving" YES,
but other species are more "sexy" to bonsai-enthusiasts.
Acer campestre is not native to Japan and had therefore not been used in "the promised land".
So no master-pieces seen on international stages so far.
(In Europe) This species is a solid part of expositions and should have deserved more appreciation, shouldn 't they?
Maybe in future ...