[hybridtupel]

I guess the reason for that is making the instructions understandable even if printing in b/w.

[shaky-carrousel]

Also it works with colorblind people. This way they can choose the color combination that works for them.

[jordanwallwork]

I think that's correct. If I were to do it for my kids I'd probably whip through and colour in the squares and circles beforehand to make it simpler for them

[scrumbledober]

I think it's just so you can choose two colors that you have and fill in the instructions.