I've worked at companies that use both Slack and Teams, and the chat culture that Slack creates is hugely different than Teams. Have you experienced both? Teams chat rooms are ghost towns compared to Slack. The UX of teams discourages chat, syncing is a mess so ordering is all funky, and good luck finding anything written in the past. Slack is so good at search that we have channels with just feeds of auto-generated information, and there's a good chance anything you need to know is in one of those channels. (company is 800+ people doing 300m ARR)