Well, isn’t that a huge benefit there? You are able to more reliably Crit with her Arts card than any other. And there will be cases where only that one Arts will pop (and perhaps another Buster) but that’s extra 100 Star weight is making it a lot more likely to Crit with that Arts and get an NP that wouldn’t have been otherwise. Essentially, it would amount to the an NP release.
Or alternatively, sometimes all you want is a guaranteed Crit because there’s a crit buff applied (say from Waver) but unfortunately the stars spread almost equally across all the DPS’s cards. That’s where Armament CC comes in and fixes that. Better to have one Crit where it counts than miss all crits due to RNG distributions.
The other this is that a 1:2 ratio is definitely significant. I mean, if* it wasn’t a rider support (200) wouldn’t be a problem with a typical DPS of 100 Star weight, but it is. The reverse case is similar.