Do we really care if the maskless person close to you is not vaccinated?

Even though this question is in the general area of covid, it reflects a true gap in my knowledge. I am truly confused about vaccine efficacy.

The Phase III studies on the Moderna and Pfizer vaccines showed about 94% efficacy. If that were the case in real life, I would not dare go maskless next to somebody who may be unvaccinated.

However, we know that in the real world, the efficacy has been close to 100%. As of April 30, the total number of breakthrough cases reported to the CDC were 10,262 out of over 100 million fully vaccinated persons. This calculates out to an efficacy rate of 99.9999%. If that is true, then why should I care if the person next to me is unmasked and possibly unvaccinated? see https://www.cdc.gov/mmwr/volumes/70/wr/mm7021e3.htm)

Unfortunately, the CDC switched gears right after the April 30 numbers. Now they track only cases that result in hospitalizations or death. As of May 24, only 2,454 such cases had been reported to the CDC out of over 130 million fully vaccinated people. This calculates out to an efficacy rate against serious Covid-19 of 99.999982%.

By the way, before anybody starts jumping on how selfish that makes me, let me remind you that asymptomatic spread by a fully vaccinated person is low. See https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/fully-vaccinated-people.html

So please answer my question. I am really, really curious.