Why would anyone “buy” movies from PlayStation. That’s not their business, I would never have expected them to be in it for the long haul, just like MS did a rug pull on this a few years ago didn’t they?
Why not? Maybe people already have an account there with payment set up, the console hooked up to the TV and soundbar and don't want do sign up somewhere else?
Furthermore, Sony Pictures is huge, so selling movies is absolutely part of Sony's business as a whole.
Who would buy movies use a TV subscription service from a laptop computer manufacturer? Or a company that sells telephones? What, are they watching movies on their old Western Electric Model 102? That'd be ridiculous.
Convenience? Maybe a belief the media would be accessible for a long time, versus the ever-changing catalog available from streaming services?
Consumers are lured into walled-gardens all the time - consoles, app stores, hardware. Where would you suggest someone purchase a digital license for a movie?
Being a media player was an integral part of Playstation since the PS2 era. The PS3 was essentially the thing that really pushed Blu-Ray over the line to really cement Blu-Ray as a movie format over HD-DVD.
Movie playback has been a thing for home consoles for decades. It became kind of a joke that the most played Xbox 360 game was Netflix. As more people have moved to streaming media/digital marketplaces, its only natural for those to grow. I've known lots of people who use their Xbox as their main media center that consume movies on Microsoft's storefront. It makes sense Sony would be in the game as well, as after all they even directly produce a lot of content themselves.
Why would anyone buy movies from another service or use another device, when they already have a console that meets their needs and that they paid a premium for? There's no such thing as multitasking, so if you try to play a game while watching a movie, you're doing each in small increments, and neither well.