This obsolete unit of distance may be better than yards or meters.
One arshin is about the distance a man covers when he takes one step forward. There are variations from one man to another, based on how long his legs are. Typically a man's step is nearer 30 inches than 28, in our day, but 28 still falls within the range of variation. Perhaps 28 was nearer the average formerly.
I started thinking about arshins and their uses after seeing an elderly Russian Mosin-Nagant rifle with its sights calibrated in arshins. Thinking the matter through, I found that I am more confident in guessing distances when thinking "how many steps?" instead of how many yards or meters. That is natural enough. A step is a familiar distance that we experience every day, strengthening our intuition about how many steps are between here and there.
Shooters often need to estimate distances by eye. Estimating them in footsteps is likely to work better than using any arbitrary unit such as yards or meters. All our ballistic data is in yards or meters, but there is no law that says we have to use those units. If we like, we can convert a drop and drift table to the measured length of our own steps, or to arshins, or to anything else. Of course in this newfangled era of laser rangefinders, guesstimating the distance may be a vanishing art, but if we are going to guess, it works better if we base the guess on the length of our steps. Or so it seems to me. See if your estimates are more accurate using footsteps; if it works for you, great, and if not, never mind.