It's all about how do you value the games you buy. Are you one of those old-school people that likes to collect paraphernalia and the memorabilia that goes with it. By this I mean having that physical copy of the game and like a child with a "new toy" like feeling of opening up the parcel from the postman, staring at the case art, reading the back cover features list, ripping open the wrapping, smelling the case, taking out the special access booklet and reading content on cars, racing history and knowledge about the cars. And then the feeling of taking the physical disc out of the case and placing into your beloved PS4 kissing the game before you pop insert it into the PS4.
I'm not sure this is a ritual most people have with their games especially racing games, but i'll guess there are some people out there that will. Those people know who they are, don't conceal it, admit it guys. LOL. Digital copies depend on the internet if you uninstall the game. And what happens if the servers go down and you had no access to your content. This is an extreme and rare example of the cost of ownership. The old saying goes with the Internet "You can't live with it and you can't live without it".
There are always insecurities with your owned content being on another computer somewhere. Having the feeling and security of owning a physical copy can give you a bit more peach of mind. Though most people won't worry and will think they will always have access to the internet and their content will always be there for them. So I say again, it's really your choice and how you value the products and contents you buy. For me owning the physical copy makes me feel better that I know I have spent my hard earned cash on something that is tangible and that I can hold in my hand and value in years to come.
And the feeling of opening and having booklets and stuff to read before playing the game also adds to the enjoyment of the feeling of being a kid opening a present and a new toy. A digital copy of a game can't give you the same smile or feeling of the true ownership in the same way and kind of de-values the game. Just pressing buy and being straight into the game isn't my feeling of enjoyment when buying a new game.