Worth noting that the author is /u/FredTesla on reddit, moderator of /r/TeslaMotors as well as the founder of Electrek. His career is essentially built on being a Tesla fanboy.

There are dozens of battery companies creating storage units, but Tesla are always superb with their marketing efforts to brand...in this case, batteries as 'powerwalls'.

This is the 'Hoover' logic of making a generic device synonymous with a brand name.