My philosophy is: I don't leave voicemails and I also don't listen to voicemails.

I text first and call later in most cases. If it's important call me twice

Yeah, I also use that to further segregate things by level of importance: there's lots of unimportant stuff coming in via that channel, so if a person on the other side can't be arsed to leave a voicemail, it's not important enough.

The SMS option just allows further segregation of important-non-urgent from important-urgent: for me an SMS might have something I should know or is good to know (say, confirmation of a doctor's appointment) but have plenty of time to deal with (say, it's in 2 weeks) so it works well for automated messages (plus it's faster to read and SMS message tend to be a lot shorter and to the point than voicemail)

In the old days of WFH I would further segregate it by "if it's really really urgent come to my desk" which further filters for importance based on the effort others are willing to put on it by coming to me with it.

In my professionally life I've concluded that a lot of unecessary stress comes from unimportant, important-urgent and important-non-urgent all coming in via the same channels and me having to treat everything as "possibly important and urgent" when most of it is no such thing, hence my filtering by-effort-required, which is not perfect but works way better than most people's approach to it.

My philosophy is that only important people have my phone number.

Everyone else can contact me by mail.