The use of a timeline is fine in everyday practice. Recorded history behind and the future in front. We can conveniently measure and compare intervals between events, make predictions etc. but can we reasonably depict time itself in the same way?
I have seen time depicted as a moving line, conveniently going across a flat surface (usually from left to right) along this line there is some moving object. In this paradigm we can describe a curve and draw wonderful conclusions.
If we look around us we see no moving timeline sweeping across the universe. We see only the existence of matter and energy.
Even if time itself does exist (I know there is eternal debate on that) how can we base any theory on such a representation?
This goes to another question: In the old fashioned steady state universe (ref. Fred Hoyle) without beginning or end in any way, could we simply exclude time as a fallacy and reasonably snub any theory based on its existence? (I'm not making a statement here.)