It's absolutely this. We've mandated something similar at our org. I hate it, but there's still something about being surrounded by people who aggressively work together for 10h a day, that's a lot of peer pressure to stay afloat and do what you can. Builds more of a team spirit as well. It's basically a way to squeeze more work out of people. Not that it doesn't have downsides, but it's really hard to make an accurate calculus here.