I don't mind both, but don't get why should I use Slack/Teams (without Active Directory integration) when for example Telegram added nice group management into

I don't mind both, but don't get why should I use Slack/Teams (without Active Directory integration) when for example Telegram added nice group management into the messenger? More feature rich then both of these, suitable for teams. Ah, no group/video calls... But in case they add group calls - the app will become pretty good for even office communication.