This type of service can be very beneficial as users are still able to craft their own messages, while a professional reads them. In doing so, companies can spend more time on the scripting process, making sure the text conveys everything they want it to. As such, companies may bring in expert teams to draft, revise, and/or finalize the script itself. The bottom line is you can take more time to get the words right. Additionally, in working with a professional voice talent, you are ensuring your words have the utmost impact—i.e. the words are read perfectly with the right tone, resonance, pacing, etc.
https://smith.ai/blog/28-business-voicemail-greetings-for-main-office-and-personal-numbers-formal-informal-modern-and-just-hilarious

There was a time once we were mad for the funny voicemail greetings, creative voicemail greetings, it seems like that time has gone, now everyone leaves WhatsApp and iMessage instead of voicemails. For the exceptions, we have prepared this article to set up custom voicemail greetings on iOS with some sample Voicemail Greeting messages for iPhone, which takes almost less than two minutes if you correctly follow the steps. Undoubtedly, many professionals still actively use the voicemail feature for office purposes.
A professional voicemail greeting is a recorded message that welcomes callers to your business when no one is available to pick up the call. For a polished call experience, the greeting should reflect who the client is calling – whether a general business number, department, team, or individual – and when the customer can expect the call to be returned.