We bought a fairly cheap wearable monitor early on, and it works. Both in the sense that it has given us a couple of false positives when it got out of position, and in the more important sense that it has only done so a handful of times and the rest of the time I sleep much more soundly because I know it would go off if our child stopped breathing.
Honestly, this is not a truly hard problem to solve, and I'm kind of amazed that the APA hasn't figured that out yet. On the other hand, obviously the effect on different parents may vary.
Don't get me wrong, I support people learning CPR. It's better than nothing.
Touche. Definitely experience will vary. In my circle of friends, we were using angelcare monitors about 10 years ago, which to be fair are more about sensing movement than trying to directly detect sleep apnea. Nobody liked them, everyone stopped after a while and decided the very small risk of SIDS wasn't worth the suffering involved in trying to detect it.
That said, one of my friends did have a son pass away (on his first birthday, no less, which is pretty late for SIDS IIRC) during the night for unexplained reasons, so I can't really blame parents for being paranoid. You have to find what works for you, and for everyone that's going to be different.
Is it strictly necessary? No. But it helps me sleep, and that means the baby sleeps better because he's not being visited and monitored by a human.
We've had one false positive in 6 months. That's an acceptable tradeoff, in my mind.