Whoever implemented it chose @ as a unique symbol to represent the top-level topic lists when not filtered to a category or tag. This is like forum.example.com/latest or forum.example.com/top. So you enter @ separately as its own entry to apply the board there.
I agree that this is confusing, but it’s something that can be ignored unless you want global kanban boards.
It doesn’t, it just complicates moving to the category dropdown because we have to also create a migration so we’re not reverting settings on sites that are already using it this way.
Theme settings are dictated by core APIs, so when we use the category list type, we can not extend it with additional options from the theme itself.
Discourse isn’t a massive company, we’re time constrained to focus on the most used features and refactoring components (which are offered at 0 cost btw) can be difficult to prioritize. If someone wants to sponsor kanban setting improvements we can certainly make it a higher priority.
Does Discord have a kanban board feature available? I looked but I wasn’t able to find much aside from a bot that integrates with an external kanban service.
You lose some control too, your users are Discord users, the content they post is also Discord’s content. When someone pays for Discord, the profit is Discord’s. There are trade-offs and costs for every platform.