It's how you do things though. But the salary employees are entitled to the full 8 hour days, even if they worked just 1 hour.
Sure, you have to get work done. If you don't get work done, what are you there for, right? Things have to be done. And how you get it done is up to you. But if you work just one hour, you can still bill the total 8 hours.
I actually know people who work 60 hours a week because they are being exploit because of a salary.