I'm currently subscribed to 3 vod platforms. What I've noticed is that pirated sites load faster, require no login, quality is either stable or blocks (it doesn't lower itself), subs in many languages and of course are full of ads, but a good adblocker can handle that.

Edit: Just looked around and I think it's more complex than that. I'm usually either on a laptop or a desktop, so I appreciate sites that focus on pc first, have low friction, are simple with no animations, and give me control (I'll tell you if I want to see a trailer or not).