I agree that the free dlc is pretty insignificant but at the same time at least they're just giving it to us instead of having it be preorder incentives or charging for it. That's the key difference. With any other developer there'd be some sort of hoop to jump through to get this stuff.
Also just look at the main game. It's pretty big. So the dlc that they actually charge for should be more in line with that. You shouldn't let the stuff CDPR is giving out for free color your view of future dlc. If anything, you should look at what everybody else IS charging you for and compare that to what CDPR isn't.
My guess would be no. It's probably a slightly different file that needs to confirm a disc is in the system but I would say, since you're going to buy it anyway, or at least thinking about it, just try it out and see what happens. Worst case scenario, you just have to delete the disc install and download the game.