Actually, there does seem to be a pixel to reality and existence according to physics, the Planck Length, and the guy (Max Planck) came up with it around the turn of the 20th century, from the math of observing the behavior of light in matter glowing from heat, aka black body radiation. He was also able to deduce Planck Time and Planck Energy.
We can't see it, though, it's smaller to a proton than a proton is to us.
Sometimes I think that I could easily comprehend any idea, as long as I carefully read about it.
...then I see stuff like this and realize there are ideas so far beyond my current understanding that I feel like I'd need a PhD to wrap my head around them.
Not really. The more correct terminology in the comic should have been 'voxels' (volumetric pixels). But it's definitely talking about matter quantization.
The holographic principle (a) is far from being strongly indicated for non-black hole circumstances, and (b) only relates to how 4 dimensional coordinates might map to two dimensional foundations.
Because they need to be interacted with and in the most extreme cases you can't track state changes for mathematically real curves without infinite precision.
So even if you start out with something that can be described using a continuous/wave like function, at the point of interaction it would need to be quantized to a discrete unit so you could track how free agents independent of the determining function might alter it.
Of course, if you want to be memory efficient, you'd also throw away that conversion to discrete units if the information about the interaction was erased, as you no longer still need the conversion to track state changes.