I asked a question about which US phone carriers allows its users to use one of iOS' features, and it got downvoted.
Apple has a Discussion page about it, but it seems incomplete.
People in the comments seem confused by the difference between "Visual Voicemail" (the Voicemail tab in your Phone app) and Voicemail Transcription (a per-carrier feature enabling transcription of voicemails inside the Visual Voicemail app).
Is that why the question was downvoted?
I thought it was because it was partly about carrier-related features but there is a Hashtag "phone-carrier" so I thought it validated the question.