I would really like to agree with you, but I'm pretty sure there's some edge case where you want to call Coins in the middle of a chain -- say you play Storyteller and you want to play Diadem with it, and calling Coins earlier on in the chain gives you more Actions so you can draw more cards. It's less difficult to come up with an example for Royal Carriage.
I remember thinking about this at length when MF was pushing out Adventures. There's not really a good way to make an interface that offers you all available legal options when theres a Throne Room chain (or similar) and you have one of these cards on the mat. It's really unfortunate but I think that's the way it is.
That said, this is not a reason to make the interface suffer for the other 95% of games. It should be fluid, seamless, and intuitive.
I remember thinking about this at length when MF was pushing out Adventures. There's not really a good way to make an interface that offers you all available legal options when theres a Throne Room chain (or similar) and you have one of these cards on the mat. It's really unfortunate but I think that's the way it is.
That said, this is not a reason to make the interface suffer for the other 95% of games. It should be fluid, seamless, and intuitive.