"Water cooler" is something that can only happen at an office. You can have two devs talking about something, but then a person from legal/marketing/art chimes

"Water cooler" is something that can only happen at an office. You can have two devs talking about something, but then a person from legal/marketing/art chimes in with their view. Or even a dev from a completely different team overhears and has some insight you don't. It'd never happen in a random chat service, people don't start water cooler stuff on public channels, they either use more limited team chats or private messages.