The point is that if you do a search on any web forum, including this one, you will find plenty of posts that basically say, "ZOMG, pulse ox is so easy, it's just a finger clip." It's essentially the same argument being put forth here. If a non-medically licensed person can do it to themselves, why can't we do it to other people?.
The difference, though, is that a person with an abnormal pulse will change treatments, even for basics. If I've got a patient with no medical history, generally normal on exam, but with an irregular pulse rate, I'm going to seriously consider calling for a paramedic. Similarly, if I'm running a nursing home call for a confirmed electrolyte imbalance, or a patient with renal problems, a non-normal pulse rate (either not irregular, or not one consistent with the patient's medical history without lab values) will get a paramedic response and/or rapid transport. An altered patient should be transported immediately regardless of what a glucometer says. If the person can eat, sure give them some oral glucose, but the value really changes very little.