It’s not a scam, it’s just a pain in the ass. If you use it right, you end up saving money.
If you’re interested in taking advantage of one but skeptical, try funding it with only the amount you can roll over and then you won’t lose any at the end of the year. My FSA (FSA feds, the one in the video) has an app that you use to take pictures of receipts to get reimbursed.