What's your usecase for this? Not sure I like making assumptions on how and where those sessions are stored.
I'd rather have a way to tell Kate to create a desktop file for them, or a button in its UI or something.

The usecase is that you can pin the sessions to the taskbar. For instance if you have a quicklaunch widget in your panel for your favorite applications.

And yeah I get the point about including this logic into Kate itself.