You made things up in order to make it simple. There's a reason why I asked how effective cloth masks are in stopping aerosols. Droplets and aerosols aren't interchangeable, yet you're trying to apply data about droplets to aerosols. If they only stop 50% of droplets their ability to stop aerosol is going to be significantly worse. I already posted a video that showed how 6 masks are ineffective at stopping aerosols, so that should tell you a lot right there.
Secondly, since emitting viral load is a continuous act, this means both (masked and unmasked) can emit the same amount, just one may take longer than the other to reach the same density. So, if we go by your 50% number, being around someone unmasked for 5 minutes would be equivalent to being around someone masked for 10 minutes. This isn't my idea of extremely effective. Again, not even taking into consideration aerosol which would tank effectiveness even further and by a large degree.
In the end, at best, you're talking a 1-2 minute difference in time it takes to emit the same viral load.