I do it with my friend.
I have Plus on my account, and set my console as a secondary console.
Then, on her console in her house, she sets her console (signed in as me) to be the primary one.
What that does, is means she can play whatever she wants from my account on her console, signed in as herself no less. She needs no internet verification, no bullshit, nothing. Once a game is downloaded to the primary console, anyone on that console can play it, and if you have Plus and your account has that console set to primary, anyone can use your Plus for online too.
Meanwhile on my console, I need the internet to verify that I own my games if I want to use them, and no one else signed in on my console can play my digital games PERIOD, nor can they use my Plus.
So basically, with PS4, you can have one console where anyone can play anything and share Plus, and you can sign in on a second and play those games and use Plus when connected to the internet and signed in as yourself.
I do the same thing with mine and the missus' Switches.