I still have the same question. Spare in this context is almost the same as save, to save time or to spare time is practically the same (in my mind). You showed that it translates differently but sparing time seems to mean the same essentially. There is something I'm missing.
I had gotten the impression that "sparen" related only to money (i.e. when you say "er wird sparen", it directly translates to "he will save money" without having to specify "er wird Geld sparen").
Is it the case then that you can use it for other things as long is you specify ("Zeit sparen" / "Leuete sparen", etc.), or is "es wird Zeit sparen" a specific colloquial phrase?