@UltraNoob
Planck time exists due to the inability to measure time in incredibly short amounts according to Heisenberg's uncertainty principle. It does
not say that objects are immobile during that time, it only says that we cannot accurately measure it.
Planck time is the distance light can travel in a planck length. A planck length is the smallest measurable unit of distance. Planck length does not say that matter is made up of planck length sized grains, only that we cannot accurately measure anything smaller.
Light is the fastest thing, but there are many things that travel slower than light. If planck time and planck length were not just an inability to measure, but a discrete frame rate of the universe, then nothing slower than the speed of light would be able to move. Every planck time, such an object would try to move a distance shorter than the planck distance but would be unable to.
@1059212
Since at least the time of George Berkeley's
Subjective Idealism, there have been people who suggest that reality is an illusion. Usually that sort of thing is unfalsifiable and therefore also impossible to confirm. But as much as anything in our lives is real, time is observable and measurable.
Fundamentally, scientific law
is observations.