> If you set it any in-between scale (such as 150% or 300%) then you will have display artifacts, such as horizontal lines appearing to have different widths when they are all in fact set to 1px.
This is only true with the approach macOS takes. When set to 150% on macOS the app renders at 200% and the compositor downscales. On Windows however there is no downscaling: the app renders directly at 150% thus avoiding any artifacts.
That is only true for apps where everything is vectors and it knows about scaling, since apps draw to the pixel buffer themselves. Many contain rasterized resources with fixed resolutions.
This is only true with the approach macOS takes. When set to 150% on macOS the app renders at 200% and the compositor downscales. On Windows however there is no downscaling: the app renders directly at 150% thus avoiding any artifacts.