Downfall vulnerability may affect Intel Macs; usual precautions recommended
A newly-discovered Downfall vulnerability found in Intel chips may affect older Macs powered by these processors … A new variant...
Do I understand correctly that as long as I am the only user on my Mac this vulnerability is basically not relevant to me?
From what I understand, yes. This vulnerability is to gain information about another user using the same computer (at the same time?). This is why I have disabled the performance-impacting spectre/meltdown mitigations on my home Windows PCs.