Like the first pCARS, I bought pCARS 2 digitally (collector's edition with season pass purchased at the same time, and with pCARS 1 owner discount applied). It seems these days when you're buying a PC game, you're going to buy it digitally (e.g. Steam, which was and is still being used for pCARS), not physically. I mean, look at some of the computers - desktop tower cases, all-in-ones, and even laptops! - they don't have an optical drive of any kind (or provisions to install one)! It seems digital distribution of games are the norm - the future is now - and it applies not only to small indies, but also big AAA titles.
Even if there's online distribution, console games are the ones more likely to be seen with actual physical disks.
(Also, we in the USA cannot buy those expensive physical collector's editions that the EU has, including that model McLaren...)