as you already know, SNMP is a hard requirement for anything beyond basic home use network. It will provide information about device, ports, wifi, temperatures etc
To get these information in some useful way, you need a program on other end which will read these data and display them in some meaningful way.
My biggest problem is: OpenWRT is primary a network router, and every network device need to be able to provide information about addresses and routes via SNMP
There is bunch of standard MIBs created for this purpose
I am using LibreNMS (yes, i send there many PR/patch in past) for monitoring, and it was very problematic to have a network device without network information
so i asking DEVs that include these few lines in default SNMP daemon to be able to get these standard information
It is not LibreNMS specific, it is SNMPD specific stuff
And believe me, when you have more than few device in network, you are blind without SNMP / LLDP / Monitoring