I like to Geocache, which I suppose is a geo-location hobby. The official website uses degrees, minutes and decimal minutes out to three digits, which I found was a very useful measure. So I can understand your desire to use this format instead of H:M:S. I’ve had to convert back and forth between formats when studying my hiking routes using, e.g., Google Earth, which is a bit annoying.
Decimal minutes, to three places, works out to 0.001 minute ~ 1.7 or 1.8 meters or so, which is about the size of a person. So going out to 0.001 minute means the smallest “tick” in the scale is the size of the geocacher themselves. Handy.
Also, the latitude ticks are always the same length, it’s the longitude distances that shrink with latitude. So the d = sqrt(x^2+y^2) distance is usually bigger than the longitude (x value) distance.
(Also, I won’t be geocaching at the poles, thank goodness)
I was surprised how hard it was to calculate without knowing the formulas but, where I live, .001 degree of latitude is about 1.1 metre (4’ 4 1/2") which is shorter than my Mom. Still quite a hike to either pole from here.
Decimal minutes sure seems like a peculiar system, to me. Degrees, minutes, seconds is a traditional method (and then if you need more precision, decimal seconds, because there isn’t a smaller subdivision). If you don’t like extra subdivisions because they make calculations harder, then decimal degrees makes sense. But why would you go halfway in between? If you’re not using seconds, why use minutes?