Living on Bitcoin means having bitcoins and spending them. Even if you need to go through third party services
But what's the purpose of this experiment then?
Many people have been living off Bitcoin for years by now, but they don't post twits and posts telling the public how they converted a few satoshi in the morning and spent the proceeds in the bar at night (where "good morning means goodbye"). Apart from some Tokyo Girl ("you've got the moves to rule the world") aiming at publicity stunt and looking for cheap popularity, I don't see any particular purpose in this "Bitcoin Survival Challenge". You can just order a Bitcoin payment card and get done with that. As simple as it gets, but maybe, it is just me, after all
The point is to demonstrate that someone can live on bitcoins. They can hold 100% bitcoins instead of other currencies and do just fine. I have done this so I know it can be done.
There are many services that are helpful such as gift cards or a third party like purse.io, even BitPay is not direct bitcoin to the merchant. Trying to be all 100% and "pure" is just silly at this stage of Bitcoin. I gladly pay for my web hosting service even if they accept BitPay instead of me directly sending my bitcoin to the merchant's wallet.
This is new to Japan so them getting the word out with stunts like this is just fine.
It's better than the journalist in the US who tried it in the early days and when trying to get a subway ticket he stood outside of the station with a sign that said "will pay bitcoin for a ticket", when he could have gone online, used bitspend (at the time) to buy a subway ticket online. His conclusion: other than one or 2 niche stores, you can't use your bitcoins.