Isn't this also just pushing the problem out? Once you get far enough out, you wouldn't be able to transition between cells because of the rounding error of the cell boundary being bigger than the cell size.
You can't represent infinite precision with finite bits so you must run into an issue eventually.
Of course but remember that it grows exponentially with the number of bits. Every bit you add one bit it doubles your usable size.
The visible universe (according to Wikipedia) is 8.8 * 10^26 meters or about 5.4 * 10^61 Plank lengths. That gives us a log2 of 205.1
In other words if my maths is correct if you want to represent the entire visible universe down to the scale of the Planck length you need 206bits of resolution, or 4 64 bit integers with a lot of room to spare.
And if you don't actually aim to simulate subatomic particles you can get down to millimeter resolution with "only" 100bits.
And that's not even taking into account that, our universe being so empty, you can probably fudge super large distances a bit (having a lower resolution at scales where the universe is mostly empty). Nobody is going to notice if Andromeda if a few parsecs closer than it should be.
You can't represent infinite precision with finite bits so you must run into an issue eventually.