Because SNMP traps often contain useful or urgent information about how a host is working, processing them in at least some way can be very helpful. It can be very helpful particularly for firmware network devices that can't use
send_nsca to submit a passive check result in a standard form, as explained in the Submitting passive checks from a remote host with NSCA recipe.
As an example, most SNMP-capable hosts can be configured to send SNMP traps when one of their network interfaces changes state, perhaps due to a pulled network cable. These traps are known as
linkDown traps. Monitoring this particular kind of trap is especially useful for devices with a large number of interfaces, such as switches or routers.
Keeping track of these events in Nagios Core is valuable...