When you get sucked into reels, you go from "here" to "there," and in the process, while you are "there," your entire whole self is destroyed. The same psychological phenomena happens to gambling addicts, alcoholics, or users of heroin. It has fewer physiological downsides and side-effects as those things; the only material loss you have is the loss of time.
But far more remarkable than that it's simply a waste of time, and rarely articulated, is this psychological loss. The destruction of the self. That echoes through a person's life, to their relationships, their self-construction, etc. It is those echoes that we are now dealing with on a mass sociological scale.
By the way. "There" has a lot of upsides too. People can be creative, productive, expressive while they are "there" too. Creating, being funny, being social, etc. That's why this is so hard.
TV and ticktock don’t need 1. You can interact with a remote or you scrolling-thumb but interaction is not required to consume.
2. Isn’t a necessity neither but people do use TV, ticktock or music to "empty their mind" by thinking to nothing else but the consumption flow. You can do that with reading, but that’s not an experience people usually like and they come back to the place their mind left.