Pushing the power button isn't exactly what you want to default to every time you turn off a computer. Granted, one press should make the machine shut down normally or semi-normally, but it's still bad practice.
That's what the power button does, is send a Shutdown command to the OS (or what you program the PC to do). It has been this way since for more than 10 years.
Might inquire as to why? I've been hearing tbis since Win95 and I don't ever recall finding out why.
Windows 95/98 was the last real OS that needed a graceful shutdown. It had to do with how the Swap Files and Virtual Memory were accessed and used in that OS. Once the NT Kernel became the standard, the only reason now to shutdown the OS are the programs that you have on the machine that are running.
I have been doing a hard power shutdown on my work laptop for the past 5 years. My company has so much crap loaded on it that it takes 5 minutes to power off normally, but only 10 seconds if I mash the power button. I hard reset my desktop all the time but that is usually due to a game locking up on me as I leave my PC on 24/7.
The only time doing a hard shutdown can really mess up your OS is if you were to hard shut it down while it is shutting itself down during the part where it resolves the working registry with the stored copy of the registry. Even that just takes a boot into Safe mode, then a reboot to last known good condition to fix that.
Of course, none of this applies to a Server. Those always have to gracefully shutdown. Especially if they are running Unix/Linux. Again, this is not so much for the OS, but the programs and data on the sever. This is because of the Data Arrays that Servers usually work with, if those are not "put away" properly, data corruption can ensue.