Does Asterisk registering with each other need optimization?

Question

linux

Hello! There are two Asterisk servers on the same local network.
1. sip.conf
[city]
type=friend
username=pbx
secret=****
context=city
register=>office:****@192.168.*.*
2. sip.conf
[office]
type=friend
username =city
secret=****
context=fromoffice
register=>city:****@192.168.*.*
It works. But in the description of Asterisk on the off site it is indicated that if the servers are on the same local network, then they do not need to register with each other. My question is: Is the ghosted configuration of two servers redundant?

Answer 1

So everything seems to be fine ... How else can they be friends? Either SIP or IAX. (it is understood that the subscribers of both * should be able to call each other)
What's wrong with the office. website says so, and where?
Maybe something was misunderstood, or it was about something else?