Why on Earth would they serve this when we have tea?

This passage from Murdoch Mysteries (Season 1, episode 8 “Still Waters”) is characteristic of British culture (where the normal thing to drink is tea or… beer):

— Oh, sir, you have to try one of these. I’ve had four this morning. It’s the damnedest stuff.
— What is it?
— Coffee. I’ve only ever heard of it. Big in Europe, apparently.
— Terribly bitter.
— I thought so too at first, but it grows on you.
— Why on Earth would they serve this when we have tea? I don’t see this catching on.
— Oh, I wouldn’t be so sure, sir.