Asking "Why does time pass?" seems like circular reasoning. The word "pass" inherently refers to time.
Time is just there and events happen in sequence. "Space time" is believed to be proven, but it is just a mathematical model that accurately describes what we experience in the physical world. I refer to the expression that says, "All models are wrong, some models are useful." It is possible that there could be a different model, but we choose this one because it tells us everything we need to know, so why choose a different model that would produce the same results? Still, this reasoning might prevent us from discovering something different, which would only happen if the "Space time" model would fail in some way.
Although "Space time" might be 100% accurate, I have logical problems with it, because it says that time is just another physical dimension. That causes people to ask why we can't travel in time, say backwards? Logically this seems like a problem. For example, I have heard physicists say that time is
an illusion, that all events past, present and future happen simultaneously, but we think that there is time because we can only experience the here and now. On the surface this seems like utter nonsense.
P.S. When I am playing speed chess, time can be both my enemy and my friend.