Good question! The reason why "qué" is more natural than "cuál" is that, at least in Spain, the use of "cuál" as an adjective (followed by a noun) is less and less common. Yes, it is still correct, but it's not very natural. We use "cuál" as a pronoun (not followed by a noun) but when a noun comes after, we tend to say "qué" instead.
¿Qué autobús va a ...? ¿Cuál va a ...? (Which one goes to...)
[In a shop] ¿Qué camiseta prefieres, la roja o la verde? [Pointing at the T-shirts] ¿Cuál prefieres, la roja o la verde?