I don't work for Microsoft, so I couldn't tell you why. From what I understand though, (I haven't used Kaizala yet, but use Teams at work) Teams uses AD, wherea

I don't work for Microsoft, so I couldn't tell you why. From what I understand though, (I haven't used Kaizala yet, but use Teams at work) Teams uses AD, whereas Kaizala only needs a registered phone number.