But it can also handle other functions, including session setup (initiating a call at the target endpoint—the phone you're calling), presence management (giving an indicator of whether a user is "available," "away," etc.), location management (target registration), call monitoring, and more. Despite all that capability, SIP is simple compared to other VoIP protocols primarily because it's text-based and built on an easy request/response model that's similar in many ways to both HTTP and SMTP. Yet, it's still capable of handling the most complex operations performed by business-grade PBXes.
Your prospects are under the impression that a brand will be always available to cater to them, now for some circumstances, a few brands might not be able to serve their prospects 24/7 which is why creating a voicemail message becomes useful.

Business Phone Systems often come with feature codes you can dial to complete a task. This includes listening to and managing voicemail.
The phrase ‘Your call is important to us’ is very overused and can sometimes come off as insincere. Instead your professional voicemail greeting should say something like ‘We appreciate your call and look forward to speaking with you soon.’