I've noticed that games like Diep.io are using floating decimal points for thin stroke lines on the grid. I have even tried this myself, by adding
0.5 to all of the positions for the grid lines to make the lines more thin.
I heard it from a friend that drawing on half pixels causes the GPU to do more work to smooth it out, like anti-aliasing. I am really trying to make my game look nice, by making the most smoothest lines as I can. How much slower is it really, and should I use it in an online competitive 2D game using Canvas?