Because typing on a electronic device is not always possible, nor desirable. Let's say you're reading a book and want to take notes, or you're learning and you write the stuff down to remember it better. Or you need to write down an adress fast.. a pen is always faster than a multimedia device! It's also not distracting.
About the schools... they surely can't be typing on a computer all the time? The time factor to write block characters is astronomical compared to cursive, - any time saved by not learning cursive is eaten up tenfold by writing always block characters.