This allows you to sketch in perspective while using the Brush tool, no need to switch between tools. Procreate, on the other hand, allows you to set up the perspective in the tool, and then apply a setting to any layer to either user the perspective on that layer or not. Sketchbook Pro has a Perspective tool, and you must be on that perspective tool in order to draw perspective lines. I think Procreate has implemented this in a smart way.
Many other programs have this, and it is one of the few tools Photoshop lacks compared to competitors. Recently I've been using Procreate on the iPadPro, and it has some features that just has Photoshop beat, and I'd love to see these things in Photoshop, particularly for desktop application.
I'm a long-time adobe user, and love the products. I know Photoshop is marketed as a photo-editing software, as it should be but it is no secret that the vast majority of digital artists also use Photoshop. Procreate for iPadPro has some awesome features that I'd love to see implemented by the Adobe/Photoshop team.
