The thing is that you couldn't buy console-games digitally from any other retailer before, Microsoft and Sony essentially have had a monopoly on their digital sales (and prices) until now. This gives some much-needed competition.
In a best-case scenario, this will indeed result in console-gamers getting similar deals to what PC-gamers are used to, which makes going all-digital next-gen WAY more attractive. This is essentially how Microsoft should've approached their vision for a digital future, instead of forcing it upon people.
tl;dr: PSN turns into Steam, which is a good thing.