Locking the PC in Windows 10 prevents your computer from an unauthorized access whenever you are not using it. It lets you leave your PC without shutting it down so that you can resume your work whenever you want to
Many times it happens that you find someone trying to break into your account. It is indeed a very alarming situation because once an intruder gets into your PC; he can do absolutely anything with your private and personal data.
One of the most unnecessary things that Windows 8 brings to desktop computers might be the lock screen you need to wipe away every time you start your machine - luckily it's also one of the things you can disable.
The reason to lock your screen (Windows key + L) usually is that you leave your computer, meaning it would be reasonable to turn off everything else there is on your computer as the sound or your screen as well.
The minority of Windows users have really ever needed Caps Lock - most of the passages written in capital letters are still done with Shift only. Because of that, most people will find the Caps Lock key rather annoying since