[Definitely both. But he seems amused at his answer, at least.]

How frivolous, but I suppose that's just the kind of place this is. [In fact, "frivolously" was how most of the Servants spent their time here, Gilgamesh included. Not having any actual serious responsibilities to attend to (like, say, the end of the world) really leaves you with a lot of free time on your hands!] Hmm, well, it isn't fun if I give you all the answers, so I'll leave that to your imagination.

[He will probably come to regret that decision.]