Cisco FMC static credential vulnerability exploited as a zero-day

There have been a TON of static creds on Cisco gear. Seems like a system wide engineering issue

https://search.cisco.com/search?query=Static%20Credential%20...

Is there an actual reason for this credential to exist, or did it just 'end up' there? (either an unfortunate artifact of testing in development work, or some other way)

Having the word "secure" as part of the product name is pretty brave, especially if you're Cisco.