My own reservation about it, is that we know very little about resilience in the face of power failures and other abrupt cutoff events.
The tools and experience with ext2/3/4 over the decades have resulted in a very robust solution that has yet to ever lose any data for me. Dunno about Btrfs.
Cheers
Good point Mark, fortunately in my location the power is quite reliable although we get a fair few electrical storms in the summer which could be a problem but we have been lucky so far (touch wood!). The critical data is also backed up off-site nightly.