Earlier quoted context omitted.
While Krita can be nice, it can also be a bit difficult and bothersome to use. For example, there is no printing support. Units everywhere (other than document creation) are in pixels and cannot be changed to millimeters, etc. Tools (like drawing a rectangle) operate on the current layer instead of creating a new one like Photoshop, which makes drawing annoying. Guides aren’t that fantastic to use. There’s a lot of a…
Why would you prefer drawing in a new layer when switching tools?
Because quite often I would like to move or resize an object (and only that object) after drawing it. Note I'm really only talking about drawing shapes, etc, using the standard tools. Not really brush strokes.