Why should I use, or not use, MSG_CONFIRM?

Question

I am acquainting with BSD sockets, and flicking through the man page of sendto, I bumped into MSG_CONFIRM flag, which is quite mysterious to me at

Answer 1

The reason to not send it is in case the mac address for the IP changes over time. If you're constantly telling your system not to check, it will continue to send to the same MAC even if the IP address isn't there anymore.

It seems the case for sending it requires a very special situation where you can guarantee things about the recipient of your messages. The overhead of a periodic ARP request is very low, so the benefits are extremely limited.