Sunleaves are the large leaves at the base of and associated
with secondary branches.

I assume their role is to feed the secondaries with products
of photosynthesis and release of stored mobile nutrients such
as N, P, K.

That being understood, what is the effect of pruning out
one or the other, as when making a plant into a bonsai?
If we're trying to arrest stem elongation by pinching back,
does it leave the plant stronger to remove just the tip in
question without removing the sunleaves?