To make balanced worthwhile you really have to design everything in the electronics to be balanced throughout, otherwise you add extra circuitry and cost for no benefit; even then, the main advantage is really only seen when you use long interconnects - this why many Stateside amps are balanced, as their philosophy is long i/cs and short speaker cables. Naim is the opposite, preferring to keep i/cs short and speaker cables long (indeed they need to be long). Neither is absolutely right or wrong, just two different ways to arrive at (hopefully) the same goal. Naim is particularly hot on the system earth to keep noise at a minimum, and this is one of the reasons why they favour DIN over RCA phono as it makes this far more achievable.
Of course, Naim are no strangers to balanced design either - witness the Statement…