Frequency conflicts are the biggest reasons for the 2.4 systems. I too started with a DX3 when I raced offroad cars for that exact reason. I was getting frequency hits all the time and it got expensive getting put in the wall. My first plane had a 72 mhz radio and worked well. Not enough people to worry about the freq hits. I recently bought the DX7 and wow. I found it to be alot more precise in the controls. I found the same when I raced my cars. I believe the 2.4 travels at a faster speed allowing for minimal delay in response when you apply input to the receivers. I still have a 72 mhz radio that I run with my trainer, but my more expensive planes run on the 2.4 system for piece of mind. I also like not having 18" of antenna as well.
If they are going to ban anyone from flying if they dont have 2.4 systems, im guessing they will be losing some members to other clubs. It doesnt seem right.