I remember being grounded when I was a teen. I was sent to my room for whatever reason...With my TV, my radio, my SNES (heheh), my books, and my phone. It wasn't that big a deal. My freshman year, I willingly spent most of my life in my room anyway getting through 14-year-old-angst. I always used to think that I was getting one over on my parents. Why ground me to my room when I had all kinds of things to keep myself entertained? As a parent, I have a different perspective.
First of all, my teenaged daughters are very different individuals. What works for one, doesn't work for the other. When the Oldest child is being punished, first thing, she loses her phone privileges. She claims that we are taking her life away. Her words more or less. She also has to come straight home after school. Depending on the severity of the infraction, she might also lose her iPad which she considers a severe punishment because she can't watch Netflix on it, lol. Grounding her to her room doesn't work because she vegges out in there all the time anyway. Sometimes, she gets grounded to the kitchen table. She really hates that.
The Youngest child, however, is a whole other story. Her goal, each and every day of her life, is to get her homework and/or chores done as fast as humanly possible so that she can go outside. She loves to ride her bike and scooter and hang out with the kids in the neighborhood. Her punishment is being grounded to her room. Just the mere threat of this keeps her out of most trouble. I can probably count on one hand how many times she's been grounded to her room. She considers it torture, not a punishment.
When kids are little, toddler to elementary school aged, disciplining your kids often seems like more of a punishment to the parent than to the child. Now, for teenager truism #4, at least when my kids are grounded, I don't have to worry about what they're doing when I can't see them.