So back to the actual question.
Yes, you expect a little much from 30 FPS.
The thing is that 30 FPS is perfectly smooth if you look straight forward on a monitor and don‘t move your view sidewards. Objects don‘t move much on your screen, only very short distances of fractions of a mm on your screen. That’s when people tell you that 30 FPS is fine as long as it’s smooth.
The moment you add motion it gets different. An object that moves quickly on your screen, be it because you look out of the side window at a tree or house or it you use a head tracker to move around these objects move a larger way on your screen in the same time and still have to be projected by 30 pictures per second.
Now imagine you have a large angle of vision right in front of your eyes and the world moves around. Can this be smooth at 30 FPS??
50 start to get smooth in VR.