You asked some good questions but the answer to "should you remove them" is probably no.
These charms provided by Microsoft make it easy to get to very settings on your computer and then make it easy to do things like power off your computer. So no I'd leave the charms there. If you ask me.
But if you really do want to get rid of them it's actually pretty easy. Just in the Windows desktop right-click on the taskbar and then select properties from the menu that appears. In the corner navigation area choose the option that turns off the charms that appear when you move your mouse to the upper right hand corner. Once you do that though they no longer appear. You can still get to them using the window shortcut (Windows Key + C) but you won't see them when you just move your mouse to the upper right-hand corner.
This is one of those things that I suggest leaving on until you just can't stand it as the charms actually are quite useful for searching and modifying settings in Windows 8.