Many of these are defaults dating back to the Unix days, particularly tar (tape archive) and gzip.
Krita (KRA), GIMP (XCF), and Photoshop (PSD) save files in a lossless internal format that preserves layers etc. Every time you open and save a jpg, it gets worse, and that's not acceptable for professional use. If all you want is to crop/draw on images, something like KolourPaint is probably a better choice.
MP4 is/was patent encumbered depending on jurisdiction.
And safety. And and and...
This is why we have change review etc.