ZFS also have a good track record of providing good safety, there are lots of success stories with ZFS. Like, when one of the network cards at CERN(?) was faulty and injected faulty bits into the data stream, but ZFS immediately detected it (from another server). CERN is now migrating to ZFS machines, away from Linux hardware raid.
So, when you say that BTRFS offers complete data integrity - that is very doubtful. Because there are many strange situation that BTRFS needs to be able to handle, and we dont know if it does. It is like you say "yes BTRFS is totally guaranteed bug free". That is impossible to promise. So I dont agree with the web page you link to. Maybe it is the goal of BTRFS, but it is a good goal.
I read somewhere (cant find the link now, can someone link to the interview I talk about?) that the BTRFS developer said he got convinced to try to add data integrity to BTRFS after Sun talked a lot about it - before that, he didnt understood the importance. Therefore BTRFS is not designed from scratch to offer data integrity, it is an after thought and add on. But ZFS is designed from scratch to offer data integrity.
Sun and Solaris developers have decades of experience from Enterprise storage and they where the first to notice the need for data integrity and the problems that arise in Enterprise server halls. And other filesystems followed Sun/Solaris. Sun shows the way to the rest. To really do complete data integrity correctly, requires VAST experience. There appears to be only one full time BTRFS developer according to your link - does he have the required experience, has he a large database of all problems that haved occured in Storage halls? I doubt that. Complete data integrity is extremely difficult to do correctly.
But if BTRFS does not succeed providing complete data integrity, it is better that BTRFS gives us just some rudimentary protection than no protection at all. Sure, XFS, JFS, ReiserFS, etc also has lots of checksums all over the place to give data protection - but in formal academic studies the protection is very bad, in reality.
In short, it remains to see how good BTRFS offers data integrity. It is good though, that people become aware of the Silent Corruption problem and requests Data integrity. The more filesystems that provide data integrity - the better for us users. Exciting times indeed!