"why do you need" is the wrong question. There's an RTC, I paid for it, it's delivered, I repaired the known problem and it's not working. So I'm naturally curious why that is.
Sure, ntp is providing ample timekeeping accuracy... but maybe I like my log entries to have the right time, even if generated before the first ntp call. Or maybe I just like puzzles. Or hey, maybe I just hate bugs. 😀