It must depend what you cook. I don't do fried, spitty type dishes and the grout around the largish tiles in my now 10 year old kitchen is as good as new. I rubbed car wax into the freshly laid grout lines, same as I did in the bathroom. It also depends on how much light bounces around your kitchen, glass being so reflective shows up smears with light on it. Just above the kettle in the first photo is a good example. Each to their own, I'm a non-glass girl whenever I can get away with it.

Moulding on the wall is a great way to create interest on the wall like this. Also consider a gallery wall. I think the polka dots would work best in a children's space, but of course your house is your castle! Do what you love.

To me, the one on the left looks like a carton of eggs and the one on the right looks more like fish scales, but perception is very subjective. In fact, since a fish usually swims horizontally rather than up and down the tiles would need to be rotated 90° to be like fish scales ... but that would look rather odd ( *smile* ).

Just a suggestion but have you thought about a deeper grout to showcase each tile a slightly deeper grey to the tile will showcase the patterns so they don’t get lost into one another.. Plus so much easier to clean! If you’re afraid to go too dark then go two shades darker than the tile.. Either way will work.. but as a professional having used similar tiles I always like to showcase with a deeper grout.. Just a thought!!