I didn't say anything about the GBA titles. I know for sure CotM doesn't have them, and I don't believe HoD or AoS do either. If they do, then I haven't been able to identify them, and so anything that was looking like one of those transition rooms was indeed just an aesthetic choice. The GBA didn't have a lot of memory so it didn't need to load nearly as many graphics per room. The DS games on the other hand had a slower load speed to maximum ram capacity ratio.
In other words, the DS would have had to load more graphics per room than could be loaded quick enough when you step from one room to another. This spurred the need for load points to hide the load time. It was really ingenious honestly.