Customer benefit: Longevity. 3x7 chains and cassette last wayyy longer than 1x9 (and usually have a bigger ratio). 9s cassettes are not wider than 7s but instea

Customer benefit: Longevity. 3x7 chains and cassette last wayyy longer than 1x9 (and usually have a bigger ratio). 9s cassettes are not wider than 7s but instead each gears and spaces are narrower. The chain then need to be thinner resulting in faster elongation (=wearing). Single speed and 3s chains last 5000km easily while 12/13s won’t last much more than 1000km.