I consider one of the biggest deal-breakers being able to snip part of your screen with a keyboard shortcut and Ctrl-V it into the client for everyone to see it

I consider one of the biggest deal-breakers being able to snip part of your screen with a keyboard shortcut and Ctrl-V it into the client for everyone to see it inline, seamlessly. You don't have to mess around with image uploaders or open image links externally in your browser. Want to send a file to someone? Drag and drop, done. No hassle and it works for everyone, in the same way, without having to explain anything, use an external website, install a dependency, or change a setting. Same as with Discord, these modern chat clients support richer content, have nicer looking UIs, better UX which draw more people in. It's more fun to code bots for them because you can make them do amazing stuff, as the output doesn't just have to be plain text, but it can also be rich content like charts, embeds, propmts that can trigger multiple actions by selecting a reaction emoji, you get the idea. Just overall a great, low friction and _modern_ experience.