even looking at it in a picture you can see it will be near impossible to clean with a squeeggee for sure and honestly small tiles and 100s of grout lines are IMO poor choice for shower walls

I would have to say that the way this tile reflects light in different directions makes it look busy to me. I personally would want something calmer in my shower, but that is me! I also tried to minimize the amount of grout in my current shower renovation, using 12 x 24” tiles.

I have it in a 3x3 on the wall above the sink in my powder room (no natural light)

Love it for the shine and texture.

I would suggest a running (staggered pattern) bond rather than stacked, it is irregular and will never line up. stack close together, no spacers, and grout with an epoxy grout

color to match the color tile, rather than an accent. You'll love it!

Lots of grout; lots of texture. Will be very busy looking. I have not used it in a shower and would not.