The primary reason that someone would want to update is if they want to use both Line 6 wireless and Wi-Fi at the same time.  It is not necessary otherwise.  There are also some small improvements to the performance of the system in the digital sense but they do not affect the audio performance (with the exception of the latency improvement, which while you can measure, you can't actually hear).

Also you can only use one mode of operation in a venue ... either RF1 or RF2 mode, but never both.  So updating may become necessary is this circumstance.