Rowing is a sport that consists of pulling effective strokes, without rush. We let the stroke train us.I seem to do better when I slow down a bit
By adjusting the rating we control how we use and develop strength: too high and we lose rest time, too low and as you say, the rhythm goes to pot (= momentum wanes).
10 meters per stroke was once a basic guideline. It could help avoid the high rate low work situation that some beginners found themselves in after setting the drag as high as possible.
If you want to race or do TTs you'll certainly increase rating, at least for the shorter distances. While the aerobic range is usually considered 18 to 23-24, the rhythm can be satisfactory at around 28 and 35 too.