It`s a very good question JC5011.
I can see why you ask.
At 25GB if you bought the game from a shop, you should get the game install disks included in box.
About two or three disks so you can install the game on your system with the key to register it on steam also.
Obviously a 25GB file Digital download bothers you in some way due to either the speed of your broadband connection.
Or if download usage and GB capping apply to you.
So I can see your need to ask the question about the Game on disk.
When you enter your valid steam code for the game it will also as i`m sure you know add it for digital download also from your games locker.
Any updates, and steam will inform you there is a new Patch for the game if it requires it for download ok.
Sadly this is the future though, and you will see less games on physical media a few more years down the line.
Digital downloading wins.
It`s cheaper than having to make a case, the cover, and press and copy the media onto a medium to supply it.