lol at some people
When your crit% gets higher sharpshooter gets used faster because you will crit more often than before.
For even duller people:
with 20% crit say you can get sharpshooter to 32% before you crit
with 30% crit say you can only get sharpshooter to 36% before you crit
12% increase vs 6% increase (i'm making up numbers here but it's basically how it goes)