It's a start but has long ways to go before it is actually useful. As is, its a way to maybe display a image you pre-made a pixel grid on over your wplace page for you don't have to go back and forth but as something like Wplace Helper for chrome, it is not.

useless for pixel art - you can't position and size pictures relative to the canvas, only relative to your viewport

Could maybe be helpful for someone. But this isn't like the r/place extension that actually puts an overlay on the pixel grid to show you where to draw. It just overlays a transparent png on your screen.