> If I use square tiles and hide the seams between adjacent tiles, will it look OK?

Square tiling is very obvious, as you can see from the first example [0]. Hex tiling shifts tiles to a less obvious pattern. Also, as I can see from the video, tiles can be rotated while hiding the seams perfectly, which eliminates repetition altogether.

0. https://github.com/mmikk/mmikk.github.io/blob/master/picture...

Is that first example comparing squaring filing with the same _fixed_ rotation for each tile versus hex-tiling with random or otherwise varying rotation?

You don't get the typical visual repetition of features along X/Y lines

You could use world position (or just some non-uniform sampling) to offset the UVs and get a similar effect, no? Is hex significant or is it just one of any number of ways to break up the uniformity?

In practice, yes, it's very common to use a shader to sample the texture with some rotation and noise. Most games have a shader level implementation to address this, and we've done that for a decade at least.

See: https://iquilezles.org/articles/texture repetition/ for a good breakdown on some techniques.

the URL should have been https://iquilezles.org/articles/texturerepetition but this is indeed a great resource