This is a very open ended question. I particularly like it for specific use-cases. It’s great for synchronous and slightly asynchronous chatting. It’s also great for any groups that wish to coordinate on work in specific areas or domains. I think it has a lot of features which make it stand out in the chatting/teamwork app field, in particular having the ability to color names in addition to having profile pictures can help to make it quick to identify things such as role. It has fully searchable history whereas with apps like slack you have to pay to get access to that. It has integration so you can build bots and other API-based solutions to solve automation and other design desires. It has a large user-base so many existing bots and API-based solutions already exist for common use-cases. I like that you can react to messages easily, allowing quick insight into how people feel about something or whether they’ve read or agree/disagree. A single profile can be used across multiple servers, which makes getting set up a one-time entry barrier whereas other server based chat/work apps like teams require individual accounts. It’s always had both voice and video functionality which work quite well and easily out of the box, but it’s not super great for sharing your screen like WebEx or zoom might be.