It doesn't matter what the specific tech is when the end result is varying degrees of controller shaking (also known as "rumble")
Of course it matters.
Variance in the controller shaking is not what is happening. It operates similar to a Tranducer which is why sound can also be created using the DualSense. In Returnal, you can hear raindrops coming from the controller. Not the speaker, the controller. You can't do that with the standard rumble technology.
So no, it isn't just rumbling. Its different frequency tones and sound. When you walk over a rocks you're feeling a different frequency tone than walking on sand or grass. Like literal diferrence.
Like i said it's fine if you don't care for it and you're not that impressed. But the DualSense is not the same as the regular controller rumbling we've had for years.