I thing some things are obvious to everyone and some may not.
First:
The most obvious advantage that consoles have over the PCs is the price, so cost.
Console prices are well under 400 bucks (or even lower), and often with some games in a bundle.
A PC for running adequate the latest games can easily cost twice that much. !!!
Second:
Let's face it, a PC can be a technical nightmare sometimes compared to a console. You can take a console home and play a game within minutes.
No OS to configure or even better - not to purchase a game, and find out later that's not completely compatible with your PC's hardware.
So, at the end the game doesn't run as you would like...
Third:
installing a game on a computer is always a bit of a gamble (for some of us anyway). You never know if it's going to work until the game is ready to be played.
And even then, if you out of luck you can expect that game will crash at any moment. (Damn, those drivers again...)
Fourth:
Another thing that you can do with a consoles more easily, is playing games sitting on the couch, or playing games with friends in the same room.
While you can do that with a PC as well, a console is extremely well-suited for that.
Fifth:
Console games are more easily to rent than PC games, and more easily to return to the retailer if someone is not satisfied with that particular game.
It is difficult (or even impossible in some cases) to return a PC game, because as you all know, it's easy to be copied.
Sixth:
Games on a Console are more easily to be played because the controller. Even if it's possible to do that on a PC as well, the controller is included in the end price of the console. So less expenses.
..and sometimes you may figure out, that some games refusing to cooperate with an particular controller.
Seventh:
Unlike games for consoles, you won't find many PC games that supports two players on one computer at the same time.
Eighth:
Consoles are very compact machines (especially the PS4), very portable, very light weight, and they consume less power as well.
That's not the case with an Desktop Computer, and it seems it never will be...