I think that proposal on github is a great idea.
It plays on psychology very well. You bought 1 BTC, but now you are a millionaire (in "new" XBT)
It will allow people to make small purchases of bitcoin without thinking that they are getting something fractional, which could be thought of as not valuable.
Of course, things will appear expensive at first: a cup of coffee for 5000 XBT, but it will change going forward, hopefully.
Then, institutions will trade "whole" BTC just like they do BRKA-A (at $183,914 a share)