What is the ⌘K command bar in Spanbox and what can I actually do with it?

It's the keyboard-first way to move around. Hit the command bar (⌘K on Mac) and you can jump straight to any app or account you've connected without touching the mouse, type a couple of letters of 'Telegram' or 'work gmail' and you're there. It's the same idea as Spotlight or the Slack quick-switcher, but across ALL your apps at once, which is the point when you've got a dozen chats and accounts. Once you get used to it you basically stop clicking around the sidebar. Fastest way to bounce between a work Slack and a personal WhatsApp mid-conversation.