When you start to read some of the studies trying to prove how effective masks may be in non-clinical settings, a theme starts to emerge. Whilst there is practically no scientific evidence that demonstrates effectiveness in public settings, there are often references to them helping with behavioural characteristics. Or in other words, masks act as a reminder to the proles that there are restrictions in place & to behave themselves.
Of course the government when starting to mandate them they used the "to make people feel safe" approach to water down the "behave yourselves" facet, but as we found out later from SAGE & Co, controlling the population was a key strategy so masks were a useful tool to this end. It would also explain the explosion of social media outrage on the July 19th proposals, particularly from the aforementioned experts. After all they are to lose the biggest public reminder of restrictions.
Its not without irony that some have noted that many of the #covidsafe measures such as plastic screens could be contributing to restricting airflows more than previously, even where ventilation is in place. So like many of the random measures taken to "beat the virus", it may have actually contributed to the problem instead of helping. Once this is all over, its not just the government that will need to be questioned.