This... this is the most comfortable part of my comfort zone :) !
I've started tinkering with this approach years ago following a popular trend of Japanese figure/resin kits painters, just for the sake of the cool anime aesthetic, than I realised that oil painters do the exact same thing when they start a new painting...
or pencilers blocking lights and shadows using just value as colour...
Everything is connected XD!!!
That simplification of reality can be the starting point, the end goal or everything in-between the two extremes but it's always always always an intrinsic part of the artistic process!
We see a roundish mass of green on top of a brown cylinder and we call it a tree:
we give meaning and names to shapes and amorphous blobs of colours but when painting the only things that matter are just those shapes and colours!
And this is a great exercise to train your eyes and mind to this way of seeing and interpreting reality ;) all the rest is just blending!