Digital artists may favor one over the other, or, like me use a mix of both Photoshop and Painter. As a professional digital artist, I use Corel Painter for drawing and painting, and Adobe Photoshop for photo retouching, image adjustments, and making composites. Painter artists.
Photoshop is so ubiquitous these days that, like Google, it's become a verb, so 'to Photoshop ' has became shorthand for editing an image.
At Mosaic, photographers ask us all the time to compare Adobe Photoshop vs Lightroom. They want to know which one they should use.