From functionality point of view I find it a bit odd that the number of technologies for file system snapshoting grows. Maybe it is just my limits in thinking: there should always be only one universal way to do a thing.
If the feature gets merged, there will be LVM, btrfs and ext4 for snapshotting, what I can tell. In general it is great that there is more than one way to do snapshotting, but is it maintainable as in kernel development and understandable as there will be several ways for a user to do snapshotting. Will LVM snapshotting get bitrot as it is old and boring, there will be btrfs and one can already use ext4 snapshots, while waiting. Is this bad technology fragmentation?
The user perspective brought me to Ted Ts'o response as it was written so that it isn't very appealing argument at first pass. Then I came to think about the user perspective as a company, whether developing technology for own service or for an end user product, can be seen as a user like it has been touted many times that "a merge needs real users". A company's use/need should not make a big difference from a casual desktop user, thus isn't necessary to argument that a feature is merged by paycheck liability, what, as argument, will bring a house of cards.
Secondly the recent talks about forking and high fences in merging: