Maybe a good use for this is as a low cost final failover. Stick it on
a random box as mx3 priority 100 and if everything else goes south at
least you'll find all the emails eventually.
I'd probably use something that's maintained for that... This isn't maintained, and back when I used to do penetration testing, attacking a backup mx was something we routinely did. Those mx records call hostile attention to the systems they point to.