Teams

Calls:

Teams is a great alternative to using personal phones.  Anyone with access to Teams can use the phone feature and make and receive calls.  

You can start a call from chat, use video, and transfer calls.  You can create call answering rules, set up voicemail and ringtones, and turn on accessibility.

If the conversation is complex or there seems to be misunderstanding in the chat, a call is a more appropriate route.  Additionally, tone and intent aren't always conveyed correctly in a typed message.  If the tone of the conversation is important (and you don't want something misconstrued), use the call option.