Re: The reason for that is
"The only people who should have access to your video and/or audio conferences are the people who have accounts created by your IT dept"
Really? Have you ever worked in a sales or a support function for example? Would you really expect your organisation's IT department to have to create an account for every support contact, customer and prospect you might ever interact with?
Furthermore, to get the missing functionality, you don't need an account with an IT department. An account set up with any random hotmal or gmail address does the same job in terms of enabling the missing bits.
Zoom manages this perfectly well with the likes of meeting registration, passwords, waiting rooms and the ability to boot people out and ban them. To improve the usability of teams, MS needs to look at some of its competition and what they currently do better.