I do think that those gadgets have a place in the grand scheme of things and scratching that curiosity itch often helps relieve concerns that a person might be having and having peace of mind is worth a lot.
Is it something that is critical for a person to have available? I don't think so at least for normal health people with no history of oxygen problems or health problems except those related to sleep apnea.
I bought an Oura ring last month. Haven's set it up for use just yet.
I had the money available in a FSA account and it was spend it or lose it. I may just end up selling it. I kinda regret it now because I know I won't use it all that much. For me peace of mind isn't that big of a deal but for someone else it might be a big deal.