It seems to me that the "pace" in which time flows doesn't matter to any of the particles in our universe (including us human beings). If time would suddenly "halt", we wouldn't even know about it. Is there some way we can be sure that time is actually flowing? It seems to me that for all we know, time could be going backwards and we wouldn't think anything is strange.
If the direction of the flow of time is irrelevant, then is the flow of time also irrelevant? Maybe "now" is just an illusion?