A free trial is intended for you to decide whether or not to subscribe. If you already know you won’t, it’s not a trial, it’s just free, and arguably signing up like that is not acting in good faith.
That being said, this “1 year free trial” of Apple TV+ is fairly ludicrous. It’s more like a public beta because they know that the service doesn’t yet have enough content to justify its cost, and the promo users are helping them create the perception of a popular service.