The rule makes sense if the minimum wage (which I oppose in its entirety) is $15 an hour. Then that $47k floor represents a 60 hour week on $15 an hour.
Think of it as a cost of living adjustment and it makes sense.
The abuse it prevents is when an employer puts someone on salary at (say) $45k per year and calls them exempt so they work the person 60 hours a week and by doing so save $2k on the minimum wage.
Like I said, I oppose the min wage. But if you’re going to have one then you also have to prohibit a path for employers to evade it.
The rule prevents covered workers from being given “comp time” when they work more than eight hours a day or forty hours a week. They now have to be paid overtime. Guess what? Many, if not most, employers simply will not allow workers to put in the extra hours. It’s just another instance of the federal government prohibiting a mutually agreeable arrangement between a worker and an employer.