People should definitely learn about these, they affect an awful lot of our modern digital environment, not just in subscriptions but all the ways companies try to manipulate our behaviour.
Ever see a cookie popup and "Accept" is a big colourful button, but if you want to decline it's behind a grey "more options" button, then you have to scroll through a dozen different categories and disable them all, then the button has some ambiguous label like "confirm cookie choices" which gives the impression you're accepting them again? That's a dark pattern.
User interface design has long known how to streamline a process and communicate with a user to increase the number of people who complete a certain task, so it's a simple matter of inverting that logic to make a task hard and obscure to reduce that number.
What's honestly surprising is that this is actually illegal somewhere. I didn't realise there was any legislation about this.