It is possible that Cazador's castle might have undergone several redesigns and this might be remnants from the process, now just turned into a fun little easter egg'ish place to explore and three puzzles to solve for a chest and that's it.
What I find fascinating is that the puzzle is entirely doable with zero thieving skills because the first two set of triggers opens doors with help of crates and the third set of triggers opens the final chest with help of crates, the whole option of disarming is just there if you don't like fiddling around with heavy crates.
I keep forgetting what the name was but an undergroundish type of "zone" related to dwarfs, I keep fantasizing that maybe there was an overambitious idea to have another underground type of zone, if any of that would even be true then its very obvious such an idea never even reached the stage of conceptualizing it with concept artists, maybe it could have been an elaborate backdoor entrance down to such an idea.
Would love to hear from the actual developers at some point in time what the whole idea behind this was from the start.. as all we really can do is just speculating like what I just did.
Underground area related to dwarves? We could have had Faeruns version of Orzammar...
I would have loved to learn more about Cazadors niece, she seemed far mor interesting than most of the other inhabitants of that palace ( Cazadors palace is a bit lackluster for me, I don't like that quest very much and only do it to help the spawns, including Astarion, and the Gur).