I'm not disagreeing with that I'm just saying it depends on the transition that they want to do. And in the video they talk about the different types that they have.
Again I'm not taking a dump on the PS5s I/O. I personally believe it's the most impressive part of the system. I'm just saying that for Ratchet the I/O changes depending on the transitions that they want to do. If it's seamless then they have assets loaded from both worlds. If it isn't then they just pull everything from the SSD. That's why some jumps have those transition screens.
The transitions are so fast that they feel like they're part of the gameplay instead of loading screens.