Sadly, as well as this preamp measures, I feel that we are in a race to the bottom aiming for the best specs by introducing unnecessary compromises.
Douglas Self has said that balanced connections are rarely necessary in a domestic environment - he has also pointed out that balanced connections are inherently noisier* than unbalanced connections, and require a lot more silicon to even match the noise specs of an unbalanced input (let alone better it).
What we have here IMHO, is the MQA of preamps - it's a solution to a problem that doesn't exist.
It is possible to build a very low noise preamp without the input impedance compromises. Even 10k is too low for non DC coupled sources, unless they have large (=>47uF) coupling capacitors in the output stage.
*electronically noisier - the balanced connection does offer improved noise immunity to EMI etc. which is a different type of noise.
This preamp is obviously without any noise issue. There is EMI, yes, but now more than ever balanced line level connections are relevent IMO. The way I see it is an insurance policy. Thing is, unbalanced connections work well, for gear that talk well to each other.
Over the years, the manufacturer's practices regarding audio ground scheme varied quite a bit. Even the AES modified their guidelines and standards. Most audio gear enthusiasts that I know that use equipment from different manufacturers and different era have had to deal with a hum in their system at one point or the other. Troubleshooting is a pain, ground loops can comes from anywhere. It's time consuming, can be intermittent, can be faulty cable, can be gear incompatibilities, can be defective equipment, can come even from gear that is currently unused and powered off, it's a pain. Going balanced mostly fix the issue of swearing a lot an costing time. That's the most obvious reason.