The first solution was immediately plain. I did not think about it. I did not read about it. I just looked at it because my eyes were drawn to it, and and the solution was simply present for me.
I did think about the second one (the allegedly-simpler one) for a very brief moment.
And then, I read the words.
But it took me longer to read and parse "is just this with extra wall material in each cell" than either of those two maze-interpretation events consumed.
(I do not think that I am a particularly slow reader.)
It seems cognitively unusual to be faster at subitizing, so to speak, the path through the maze in which the cell exits are camouflaged, than the plain maze. It would have to be confirmed by proper experiment, with the subject is shown a decent number of mazes of both types, and hits a key as soon as they see the path (plus whatever refinement are deemed appropriate by experimenters experienced in this area).
Yep, just came here to say this. I was going to run their maze through a photoshop filter to remove the extra garbage to see what difference it makes. (but eh, we know it would)
E.g. this:
Is just this, with extra wall material in each cell, reducing the aperture of the passages: