There are jobs the electric tools can do that human muscle can not. Try boring a quarter inch dia. hole through an inch of case hardened 4140 chromemoly hand drill and get back to us.
Or just will do massively better and faster - I just had to drill through 3 layers of masonry to run new lines at work. I'm sure I *could* have done it manually, but the hammer drill I had did it with a nice clean inch wide circular hole in only a few mins. The best tool for a job is the one that lets you get it done right, get it done fast, and move on. It's nice to make sure you have a manual backup around, but electric tools get the job done for most people.
The most difficult thing in the world is to know how to do a thing and to watch someone else doing it wrong, without commenting. -- T.H. White