Second:

Of course it makes a difference. Because those are two different things - masks and respirators

Dude, think about it. The aim is to prevent infection, right? It doesn't matter one bit if you stop infection by blocking the virus on the way out from an infected person, or blocking it on the way in to an uninfected person. Either way the virus is blocked.

You keep going on about respirators, but unless you are talking about those completely sealed environment suits with their own independent air supply, they're all just air filters. In other words masks. We can argue whether disposable surgical masks are more effective than reusable N95 masks, but as far as stopping infection, there is no good evidence that either works better than the other.

Smaller R0 number does mean fewer cases and nobody said that.

Ah jeez, of course it does! Slower spread results in fewer cases during any fixed period of time, like this week. If we report number of cases each week, and there are 100 cases this week, with R=2 the second week there will be 200 cases, the third week 400 cases, and so on. (Exponential growth.) But if R=1, then there will be 100 cases in the second week, 100 cases in the third week, and so on.

I'm not even going to click the link

Of course you're not. You might learn something. Can't be having with that.