I think that's a bit of a data presentation issue
the difference between 10.2% and 13.3% is actually 30.4%. As in, team B is 30.4% better than team A.
You wouldn't really expect teams to be like, TWICE AS GOOD at a granular skill that literally everybody chases and values, right? That doesn't track with most of the other stuff in baseball; you don't see teams with .250 OBPs and teams with .400 OBPs, it's more like .280 to .330.
You actually see these types of issues all the time in medical statistics that the general public has trouble wrapping their heads around. Like you'll see "QOVID20 kills 0.1% of infected men and 0.5% of infected women" or something like that. People on Facebook will say "women are only 0.4% more likely to die than men, QOVID20 does not discriminate, don't be scared ladies!" and it's like, no, you are FIVE TIMES as likely to die as men! You should be scared.
On the team level, three extra whiffs per 100 pitches is a lot, over the course of a whole season. Even think anecdotally, imaging it's one pitcher throwing a 100 pitch outing... three extra whiffs could mean one extra strikeout and two less balls in play. Could be a big deal even in that one start. Would be meaningful for sure across many starts.