Metric time is about factors too, but it prioritizes the factors that simplify the comparison across (literally) many orders of magnitude. This is way less helpful for everyday life because we usually only reason within 2-3 orders of magnitude, but we deal with tons of harmonic subcycles that the 24h clock makes easy.
For a fun, a more justified usage of metric time, check out Vernor Vinge's "A Deepness in the Sky" (also IMO one of the best sci-fi novels of all time). A spacefaring humanity that stretches their life across journeys and projects that span centuries, and which has to artificially produce their own daily cycles, gets a lot more value out of metric time.
Came here to mention/contrast Vinge's metric time with with my (quick, approximate) understanding of this approach...
The problem with this approach is it attempts to "redefine" hours and minutes... part of what I liked in Vinge's/Deepness' approach was, it ignored all that and just talked about seconds in standard exponential scientific notation... it makes a lot more sense in space though, where there's no need/logic to connecting or synchronize to a specific solar cycle, so they just think/talk in kilo-seconds (about 40 mins) and mega-seconds (about 11.6 days)... or at least those are the two I recall them using enough that I got semi-used to thinking in them while reading the book... I had to convert, but I didn't have to redefine any existing unit or remember/remind myself which meaning of hour/minute they're using, because nothing changed.
I'm a huge fan of both, but you're not the first person I've heard who had problems with the writing style / dialogue / characterization of Fire. In that respect, I'm not sure Deepness will feel different. Vinge has a pretty consistent style and cultural stance, which IMO is an interesting balance of Heinlein-style techno-libertarianism and genuine "humanism" (which extends to dogs, plants, and other thinking creatures).
Structurally, though, it's pretty different. The characters have much more opportunity to develop, and it's purely hard sci-fi where Fire used its setting to veer into fantasy ideas. So my biased advice remains: give it a shot :)
For a fun, a more justified usage of metric time, check out Vernor Vinge's "A Deepness in the Sky" (also IMO one of the best sci-fi novels of all time). A spacefaring humanity that stretches their life across journeys and projects that span centuries, and which has to artificially produce their own daily cycles, gets a lot more value out of metric time.