Businesses should be read between the lines. Hashicorp is obviously not making a profit from its open source tools and turns it into closed source. It is an experiment and if it fails Hashicorp will loose interest in the products. In that case, the customers that actually paid for it is in trouble because a BSL product cannot live a healthy life if the original authors loose interest.
Open source is good for customers not (just) because they are cheapskates, but because it makes sure that the product is able to live on, even if the original publisher looses interest. It also tilts the balance of power to customers so that they are somewhat protected from software publishers behaving erratically, like Unity did with its game engine.