where no directional control is required and where the lean is too severe for bore-cutting because the holding-strap will rip. i use the coos-bay alot in combination with rigging for instance when swinging around large braches that are mid or tip-tied.
annoying to splice (very baggy and the core will migrate out of the throat if you‘re not overburrying) and 12mm is more like 14mm which might not matter for most.
i stuck a 24“ bar on a 290 out of necessity, worked ok for straight cut‘s in oak. would‘nt wanna attempt diagonal cut‘s with such an underpowered setup.
i will use round chain when it‘s dirty wood time because i‘m faster at filling it on the jobsite. for filing my square chain‘s i prefer a vice and good lighting.