It seems to me that the usefulness of a pulse oximeter depends on the progression of the disease. If “low osat” comes before “fever etc”, then a pulse oximeter would help you move from “low osat → fever etc. → see a doctor” to “low osat → see a doctor → fever etc.”. But if “fever etc.” comes first, I would think you would be at “fever etc. → see a doctor → get osat measured” regardless of whether you have a pulse oximeter, and so I don’t see how the pulse oximeter would be useful.
This is useful in case you have facing a choice of riding it out at home and going to a hospital with high probability of getting infected if you’re not already. E.g. if you have fever chances are still high you’re just experiencing regular flu, and should not go to the hospital, but if your oxigen starts dropping into the danger zone you need to go.
It seems to me that the usefulness of a pulse oximeter depends on the progression of the disease. If “low osat” comes before “fever etc”, then a pulse oximeter would help you move from “low osat → fever etc. → see a doctor” to “low osat → see a doctor → fever etc.”. But if “fever etc.” comes first, I would think you would be at “fever etc. → see a doctor → get osat measured” regardless of whether you have a pulse oximeter, and so I don’t see how the pulse oximeter would be useful.
I googled around and don’t have a great sense of what the progression is, but it seems that the fever comes before the more serious respiratory stuff (source: https://www.businessinsider.com/coronavirus-covid19-day-by-day-symptoms-patients-2020-2?op=1).
This is useful in case you have facing a choice of riding it out at home and going to a hospital with high probability of getting infected if you’re not already. E.g. if you have fever chances are still high you’re just experiencing regular flu, and should not go to the hospital, but if your oxigen starts dropping into the danger zone you need to go.