I can send messages, images, files, links, it supports youtube miniplayer for links, and I can start audio calls all in a singular app, and I can control which members of a channel see those messages or access that call very simply with roles. They also store that message history for years and years, idk what the limit is for channels but for DMs I can scroll back at least 5 years no problem. This works both on Desktop and Smartphones. I don't know of any other programs or apps that do all of that, please correct me if I'm wrong.