A final product is delivered/posted usually as jpg, tif or png, (not animated images) the usual universal formats. Once our artistic work is done, we can conserve kra files as ideal backup files
However, given the speed of nowadays, backups loose their value after a certain time span, i made this experience over the years.

Krita could keep its kra files in a project directory (without to bother where our files should be saved). If the user wants to get/move the files elsewhere, no problem. Krita would pick from the project folder and help us to choose another location. The name of a file would be given right from the beginning with the "New" dialog command and the confirmation of the same.

Concept:

a) Write every new file to a "project folder" stored in one of kritas application support folders (or their like), instead to bother us users if we want to save our files…

b) we users could retrieve our files, of this "project folder" from within Krita with "get file" or their like 

c) we can move these files somewhere else or delete obsolete files if we want.

in short, our files are stored all in the same folder. (Maybe also an user defined folder ?)
I think, all this could be a nice experimental feature. "im tired to save files"