I'll stick to my general opinion:
Stay away from me with voice messages!
Can't just read them anywhere, but need a quiet and private environment. Takes way longer to understand, doesn't have search, … just plain annoying.
But … "voice" messages, that aren't a replacement for written communication, instead providing cute noises (meows, barks, ekks, chirps, undefined cutie sounds, etc.) … that's a different story 