For a live leaderboard watched by thousands, polling kills the server. Push delivery and rooms change the scale entirely.
A live dashboard (sports, markets, fleet tracking) must push updates to many clients without collapsing. The reflex of polling every second does not scale.
Push, do not poll
The server aggregates sources at a controlled rate (a cron syncs, say, every five seconds) then broadcasts state to connected clients over WebSocket. Clients no longer ask, they receive.
You split into rooms: a client only gets the streams it watches. You send deltas rather than full state, and batch updates to limit bandwidth.
Hold the load
The sensitive point is the number of simultaneous connections. You size the rooms, cap the emission frequency, and plan clean reconnection when a client returns.
Perceived freshness does not come from emitting more often, but from emitting just what is needed, to the right client.