Yeah but selling physical copies is not as convinent as buying it on steam or buying keys in any other web page. I would guess "owning" a digital game does not come with all good feeling that physical copies do. Imo "but digital" argumeny is perfectly valid if it is making things much more conveninet.
Also hard copies gets destroyed over time while a steam key last forever.
Also hard copies gets destroyed over time while a steam key last forever.