It's been a long time since I've used a rangefinder. My first camera was one, a little Minolta. It was a 35mm camera. I remember when I got it I wanted an SLR. I thought I would prefer focusing on the full image rather than aligning the "dots" in the viewfinder. When I first got it the dots were a bit of a challenge. This approach seemed indirect and abstract to me. I was about 8 years old. I got used to it though. I'll have to see if I can find it.
My second rangefinder was a Rolleiflex, medium format. It was a hand-me-down. I looked up the serial number; it was made in about 1945-46. The Rolleiflex was quite a different experience. There were not dots to align; one focused the image. I liked that. But there was no viewfinder, rather one looked down through the view screen. The image was up-side-down It was a very different interaction than looking through a viewfinder. I preferred looking through the viewfinder, but I liked the idea of focusing on the image. I also liked the large format. Although it was square.
My penultimate camera was (and still is) a micro-four thirds style. Not an SLR, but it does have a viewfinder and you do focus on the image, not some dot. It also has autofocus. It is a nice camera, lighter and less bulky than most SLR, or DSLRs. Body and lenses too. Yet, the sensor size is smaller. 2/3s the size of many DSLRs and 1/2 the size of a full-frame camera. The sensor size is partially about the image quality, but also about the effect that one can get with a larger sensor.
Now I'm back to a rangefinder. It has a viewfinder. It's full frame. It has a dot to focus on; may be two if you count the one on the front.
I read some fellows best practices and he said two things:  alway shoot wide open  for indoor shots shoot at ISO 800; for outdoor ISO 160 or 200. The provider of that advice notes that while the lenses of many manufactures achieve optimal performance at 2 to 3 stops above their widest opening, Leica lenses perform across the scale. There may be some dispute here, but for argument's sake I'll accept it. Setting these two adjustments leaves only one variable: the speed. This mode will drive a specific character and style of photography.
I always wondered why people who shot with these types of cameras shot people, street scenes and often in black and white. May be the best practices above explain it. I've only had the machine for a week or so. May be later on I'll have confirmation. But I will say I have urges to do the same. May be its nostalgia.