I haven't found a way to limit reverse (i believe this is a requirement at most tracks?) on my receiver so it may be worth it purely for this reason?
You'd always switch off reverse on the ESC rather than with the radio. Although the rules are normally no reverse, the main thing is not to use reverse on track (rather than have it switched off on the ESC). However what you will find when you program the ESC to remove reverse is that you can be more confident on the brakes (sometime you can activate reverse accidentally under braking).
As said above, there is not much requirement for most of the settings on an ESC (boost/turbo are very rarely allowed now), but it's worth having the card to allow you to set drag brake (if you want to, I would suggest that you don't run it at first), and to switch off reverse properly.