BG3 is single player offline game, mainly distributed globally through Steam (and GOG) which runs it's own CDN for games. There is a multiplayer mode but that is co-ordinated via p2p for the most part.
The "IT team" at Larian doesn't get hit with those downloads as they only send a single copy up to Steam's CDN which handles the traffic (perhaps some backend user authentication too?)
so essentially this article is "Baldur's Gate 3, is a very popular download on Steam" just buzz to push more sales presumably.