Playing devil's advocate, it works from a consumer perspective too, as you're maintaining the ability to be able to benefit from the second hand market. That €100 euros (or whatever it ends up being) is worth more than just being able to play UHD movies. If you consider the potential money saved over the life of owning the console, can you justify the digital version from a buyer's perspective?
Unless you're a "release day buyer" I'm not convinced that you save massive amounts going physical.
Then the resell, do people actually resell their games that often and by the time you are looking to resell, the prices are through the floor anyway.
If you've got a copy of GTA 5 on the PS4 right now, you're gonna be hard pushed to get more than £5 if you wanted to sell it.
I do fully agree that if you're one of these people who must have a game at launch or, within the first couple of months, I personally wouldn't be buying a Digital Edition. However those who are know this, it's not going to come as a surprise to these people.
At the time I tend to buy - so usually around 3-4 months after a release, then I'm not saving as much with physical over retail.
Don't get me wrong, I'll be buying the regular version - but I can see why the digital edition will be tempting for a lot of people - those who are all digital now, those who are mainly digital now and these people wouldn't be going into a "Digital Edition" purchase blinded by the £100 saving alone.