As I've said before, if PADI would devise some globally acceptable way of teaching the concepts to which tables relate, then PADI could get rid of tables. But there are lots of dive regions in the world where computers are still not readily rentable, and teaching tools have to be fairly basic due to lack of resources. Tables remain a reasonable teaching tool, even if not very good, until PADI can replace them with something else that can be used worldwide--which will not be very soon.
When I mentioned that I taught deco theory without any use of tables, I said that I used PowerPoint presentations. The reply was that some remote places do not have the technical ability to use PowerPoints. I did not respond then, but I will now.
First, PADI requires that students view either a video presentation or a DVD presentation. If they can do those, they can see a PowerPoint.
Next, you don't need a PowerPoint. I did pretty much the same thing with drawings on a whiteboard before I made the PowerPoints. You can also use pictures. You can even teach it without any visual aids of you really need to.
Mark Powell's
Deco for Divers explains deco theory far beyond anything an OW diver needs to know with once showing how to use a table.
Not only is it possible to teach deco theory without tables, I believe using tables to teach deco theory is an inferior way to do it. If you know anything about
interference theory, you will realize that if you are teaching two different things at once, learning one will interfere with learning the other. If you want to teach deco theory, then teach deco theory. Later on you can teach how to measure it, using whatever device you want. I believe that if you teach the two together, students will focus on the mechanism of using the tables and will not understand the theory behind them.
Finally, remember that it is an option. Students who don't want to buy a computer can use the tables. In fact, so far I have never taught a class that was computer only.