Physical as it has resale value. Other aspects are the same such as install size. You'll still going to use the same amount of HDD space as a retail install size is the same as the digital one. PC has the beauty of adding more HDD space so digital is the better option, besides most PC games today are serial locked on Steam or Origin etc so the disc is useless once activated.
All that really matters is your internet connection speed for downloading where a disc could save you time and if you wanted to sell the game in the future.
You can add more space to the consoles too, easily for the xbox one, and just a bit of time to do on the PS4.