Yes.. As you see in the databook
When kamui is Initiated, the s/t is activated, and dimension warping happens... That means, anything before kamui's initiation , cannot be a space time jutsu, as the jutsu is not activated yet...all you have is chakra , not yet molded into an ability.. and Chakra itself has no space time properties.. this is why even the yamanaka clan have to propel their chakra to the enemy to take them over..
That's as simple as I can explain that part..
Once everyone understands why it's impossible for chakra to attain space time properties, i'll move on with my next argument
Kamui works with the same principles of sharingan genjutsu, the chakra is propelled from the eye to the other person, but in this case, you focus on a spot, the chakra goes to that spot then the jutsu activates , sucking everything into the barrier in the given location, thus why kakashi missed deidara a few times.