Yes I referred to the correct hemisphere.
The right hemisphere is visuospatial. Also, the right hemisphere 'sees' time/process.
The left hemisphere puts together contextless symbolic model. So I see where your question comes from: the left hemisphere can do the contextless proofs. In this case (and in many cases) the more complex solution "works" and the left brain can "prove" it works.
But a 'simplicity' proof seems better suited to the right hemisphere (I am no expert here, mind you) .... So in my anecdote the "simpler" solution is the one that I would guess the right brain "sees" as simpler: i.e., it is visually much smaller, also much easier to manipulate (over time), etc.
The book is "The Master and His Emissary".
I've noticed in myself a tendency towards programming "aesthetics" that just "feel" right. Sometimes that intuition seems to overlap with faculties that help avoid complexity and find elegant solutions... but there's also plenty of times when it's either habit based in a collection of odd assumptions or even apparently arbitrary, and so it's something I've been working to interrogate.
OO approaches specifically have something like three decades of pop-tech discussion as being professional and sophisticated. That's a kind of conditioning that's hard to overcome.