ASM: is it mandatory to have a syslog server?

Hello,

One of our customer, do not have a Syslog server (neither remote syslog or HSL). It uses only SNMP pollong/traps and SMTP to send legal/illegal requests.

Do you think it is doable to run a PROD environment like this or are there an messages which are available only on syslog?

What are the risks of running a PROD environment with out a syslog service?

Thanks!