Calling it a scam is completely inaccurate, scams rely on people not being aware (on some level) of what they're signing up for, and on people making promises they don't intend to keep. Here it is perfectly clear what everyone's getting.
Tons of people would prefer a 4-day in-office work week over a 5-day remote work week. You may not, but there are many who do.
They tell people they will spend 20% less time to work-related activities which as I said is a lie.
Not only will they spend just as much time for work, it will be more unpleasant and more costly than working from home.