1) Side effects not much more than the most tame of drugs, like aspirin. This one, if it exists, is incredibly rare.
2) You can stop taking it, obviously. Just like any medicine, the effects will wear off, but there's no rebound effect or risky side effect from coming off. You simply return to your previous state.
3) There's more positive anecdotes than negative basically wherever you look. I have a friend who took it and while he lost 20% of weight, he plateau'd - I asked him if he was going to cycle off it and his answer was an emphatic no - I asked why, he said beyond the positive weight effects it: massively curbed his weed addiction, curbed his social media addiction, improved his sleep, and because his compulsive behaviors were down he was doing better at work, reading books for the first time in years, and going to therapy which had helped his dating life. No joke, I was floored at how ridiculous the answer sounded, especially as this was a pretty bro-y friend. Yet I've heard many anecdotes like this from others, one friend stopped a 15-year pack-a-day cigarette addiction they'd had since high school.
4) Some of the other positive trade-offs: reduces addictive behavior, heals heart/bones/brain, dramatically reduces inflammation and can fix inflammatory disorders, positive early studies for Alzheimer's and Parkinson's, etc.
5) There may be no completely free lunches, but there are nearly-free lunches all the time for people with ailments. If I have debilitating GERD, there are antacids that essentially save my life with only mild side-effects. If I have bad eyesight, glasses are a miracle cure. This is all over medicine. If I'm getting surgery, 100/100 people will choose the mild side-effects of anesthetics over the pain.