To be honest, I'm surprised this didn't happen years ago.
Firstly, I'd be surprised if the confirmed seats are available more than a few days before the date of departure and only then if the flight looks to have sufficient seats likely to be commercially unsold.
As a regular commuter, I rarely fail to get a seat on a flight of choice - albeit that choice is carefully made after studying seat availability and a few other factors.
This process will, in effect simply adjust unload categories and generate more revenue.
Like most I always purchase an upgradable ticket as it gives me a few more chances to get a seat on the flight. For that same reason I will now often have to buy a 'confirmed' seat at apparently significantly greater cost, in order to retain the same relative onload category.
The same number of Staff passengers will be listed, they'll just be onloaded in a different order and Staff Travel will rake in a few more dollars.