SUMMARY
If you create a new image with any size unit other than pixels, it displays as points in the select shapes tool options from then onwards in the session for any new or opened document.

If you open or create a document initially in pixels, that document will display as pixels even if you create another document in points. So it’s local to the document in the session and is not stored in the .kra file.

Full context thread: https://krita-artists.org/t/select-shapes-tool-dimensions-in-pt-instead-of-px/76398

STEPS TO REPRODUCE
1. Create a new image with any size unit other than pixels
2. Create a vector element
3. Select it with the select shapes tool
4. Check element size in tool options docker

OBSERVED RESULT
Measurements are in pt.

EXPECTED RESULT
Measurements are in px.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION