defrag vs autodefrag

[Donald Pearson <donaldwhpearson@gmail.com>]

I read an implication in a different thread that defrag and autodefrag
behave differently in that autodefrag is more snapshot friendly for
COW data.

Did I understand that correctly?  I have not been doing defrag on my
virtual machine image directory because I do use a snapshot schedule
and the way I understood things, a defrag would basically decouple the
live data from the snapshots and greatly increase utilization.

It sounded like autodefrag does not have this problem?

If that's true, is there any case where it would not be best practice
to mount with autodefrag enabled?

Thanks,
Donald