This is the 21st Century, who needs hand tools? Well, quite simply everyone does!
I'm not saying hand tool woodworking is for everyone and I have no illusions that people coming to my classes will or even should be green woodworkers. To be quite honest I have nothing against power tools. I have adapted the use of only hand tools as a way to help me better understand history as well as share it with others. What I'm saying is that EVERY woodworker has something to learn from our history. There was a time when I relied on power tools almost exclusively so I can say from experience that there is quite the void for those not familiar with hand tools.
There are often times when power tools are NOT the most efficient or even the easiest way to accomplish tasks. Most modern woodworkers have a Dado stack for their table saw - how long does it take you to install a dado stack and be ready to make a dado? Remove the regular blade, install the stack and shims, set the fence and make a test cut. Now, compare this to picking up a dado or plow plane and making the rabbet or dado. Don't forget you still have to remove the stack and put it away then install your original blade again after! Granted, if you have a hundred feet of Dados or Grooves to make the table saw will win but for a small shop such as mine and those of most hobbiest making single, one-off, pieces hand tools will win out 8/10 times.
This advantage isn't reserved to making Dados and Grooves alone. Most woodworkers have a 6 or 8 inch jointer and a 12 or 13 inch planer. So how do you face joint lumber? Rip those nice 12 inch boards down? Build a giant router sled that takes up your entire shop? Build a planer sled? I suppose you could do one of those things or you could use a Scrub Plane or an inexpensive Fore Plane and joint the board in a couple of minutes.
Once that board has been planed is it ready for a nice finish? Certainly not. Would you rather spend half an hour sanding or 10 minutes with a smoothing plane or scraper plane? I can tell you which is healthier and much more enjoyable!
To sum it all up, I don't think every woodworker should be a hand tooler like me but I do believe every woodworker should have the tools he or she needs to enjoy the craft. We, as a woodworking community are forever chasing the latest and greatest, biggest and baddest new tools available. The truth is tools do not make the craftsman and the most important tool you will ever posses is knowledge and experience. By adding the knowledge and experience of proficient hand tool skills to your shop your productivity and more importantly your enjoyment of the craft will increase - what more could a woodworker ask for?