Omicron is 70x more infectious in the Bronchia, and one tenth as infectious in the lung cavities where you can get pneumonia. Because it is replicating in the bronchia, you are more likely to breath it out, and this is why it spreads so quickly.
Yes.
Unless you are stupid enough to wear a mask everywhere, you will clear the infection quickly, and you won't build the pathogen enough to mess up your lungs. So far, I understand that nobody has become seriously ill from it, but many people have reacted badly to the booster injections.
No. Omicron does appear to be far less severe on average than earlier strains. However this doesn't mean that no-one becomes seriously ill, and no-one dies. One plus to it is that if some people are unwilling to get vaccinated, then it is better they catch Omicron to build up some immunity with less (but certainly not zero) chance of severe illness.
It appears that in nations with high vaccination levels, Omicron could be the start of the end of this thing. But of course many nations have low vaccination levels, including in sub-Saharan Africa where this variant arose. So rich nations are still susceptible to dangerous new variants unless they start sharing vaccine supply a lot more with others, particularly the global south.
