Well. If you are specializing in 3D mechanical design then symmetrical tools are an asset -- but represent a short cut, not an absolute. Organic modeling...not sure why one would consider a symmetry tool of great value, as nature, on an organic level, is not symmetrical. The U.S. Manned Lunar Mission managed to do fine with organic humans using drafting boards and manual symmetrical drafting. The LEM (Lunar Excursion Module) used a computer that had less power than todays scientific calculator, and landed fine with non-symmetrical input from this little CPU, and the organicnon-symmetrical human astronauts.

So what is this overtly big deal about symmetry anyway? The greatest technological achievements in human history were done without it.