Here's a funny story. At one point bcache development was funded by a startup (which I won't name here). They were using it as the local storage layer of a distributed storage product. I worked there for a year in 2014.
Apparently they were not aware of the fact that bcache was a) GPLd code, or b) developed before the company existed, first as a hobby project and then at Google. After a couple of years, they noticed that Kent was in fact posting the bcache source code on his personal web site. At this point they fired him and threatened to sue. I quit the company then (along with a number of other people, for mostly unrelated reasons, such as the fact that the CTO was a notorious brogrammer). Kent got a litigator and when it was made very clear to them that they had no case, they backed down, but not before wasting a ton of money.
As far as I know, they're still actively violating the GPL by shipping a product containing modified kernel code in it without releasing the source, nor do they acknowledge that they did not develop the key component of their product.
The "commercial" version had a rather broken and messy snapshots implementation and had diverged a bit from the open source bcachefs at that point, mostly because snapshots were poorly implemented. It's also kind of funny because after we left the company we still knew of some tricky data corruption bugs, and it's likely they're still there in the "commercial" version, because backporting the latest fixes would be non-trivial and I don't think their testing or development methodology would have caught them.
Anyway, I gave up on startups and enterprise storage after this, but Kent is still developing bcachefs on his own time and money, so if you use it please consider donating some money to support its development.