I use Box2Ds terminology. "world coordinates" and "screen / pixel co-ordinates". World co-ordinates are never called pixels, they are meters or centimeters, even if historically they were derived from pixels. This avoids confusion.
For 2D games, I prefer to use world coordinates based on the pixel scale of the source art. If I had 32x32 tiles, then one tile would also be 32 world units wide and tall.
This makes it easy to 'measure' distances from source assets.
Another fairly nice scale is one unit per tile, which can simplify any logic dealing with the tilemap.
Meters rarely make sense in a 2D game, IMHO. But if you use Box2D you may be forced into a real-units scale (Chipmunk is quite happy with a pixel-based scale though).