Honest question, what do you believe is "the most popular distro"? Professionally, I have never seen a BTRFS deployment, nor any of the distros commonly at the top of Distrowatch (Manjaro, Mint, Elementary...).
With the fragmentation of Linux, even the "most popular" distro may hold a tiny market share. The guys at dropbox probably know far more about their users than what is reflected in some arbitrary popularity contest, so I doubt it's either ignorance or stupidity that led them to this decision.
Ubuntu uses ext4 and the default is to ecryptfs the user's homedir.
Edit: Actually I can't find that it was ever the default, but it was a pretty prominent option so I assume this decision is going to mess with a ton of customers.
I'd argue that the normal thing to do in the Ubuntu installer is full disk encryption, rather than homedir encryption.
Both are checkboxes, though, so one could select whichever they wanted. Full disk encryption is the most sensible one, though (better evil maid protection).
I would never attempt to use btrfs again in any environment. But if it is used, I hope the person has extremely strong backup policies in place for when it eventually crashes.
I've used it for the past 4 years as my primary development machine. Never once had an issue. However, I used Arch Linux, which always has newer kernels. I know there have been some bugs on other distros which run older kernels.
Fair point - I'd be fairly confident that it's Ubuntu at least on the desktop, based on experience the data I've glanced at previously. But I could be mistaken.
With the fragmentation of Linux, even the "most popular" distro may hold a tiny market share. The guys at dropbox probably know far more about their users than what is reflected in some arbitrary popularity contest, so I doubt it's either ignorance or stupidity that led them to this decision.