Which isn’t much compared to the amount of space-time that gets manipulated during the series. Literal time travel, giving items more space inside, than that take up externally etc.
Most of the spacetime manipulation are still within the realms of physics, or at least can be reasonably described as long as you change a few assumptions e.g. the existence of negative mass, an infinite energy source etc. Only the time turning and fidelius have actual philosophical implications and former has been thoroughly studied and debated in both normal philosophy and natural philosophy.