Difference between Common Area Phone and Phone System/PSTN licensing?

[Bob Manjoney]

The Common Are Phone SKU continues to perplex me. What *doesn't* it come with? In other words, why wouldn't I just purchase a bunch of CAP licenses for my users who have no need for the O365 suite/email/SharePoint etc. but just need a phone with voicemail? Is that viable?

[#2]

I don't think Common Area Phone includes voicemail. Phone System voicemail requires an Exchange mailbox to deposit messages into and the CAP license only includes "Skype for Business Online (Plan 2)" and "Phone System".