I only wish your own comment here would be appropriately rewarded, as it truly was a sup(poo)rb read. I believe the correlation you noticed between toilets and quality writing is significant; in fact, perhaps a platform called "Steemit" is subliminally calling on us to make something of our previously underutilized bowel movements.
A friend actually offered a translation of said button: "test." Now what it's testing is still anybody's guess. The mystery continues...
RE: Pooping in Japan: August