Oral airways can be easily learned - just a few minutes. I've never seen one do any harm. The worst I saw was when someone used too small of one and it fell back into the mouth. But it was easily retrieved.

Nasal airways take more skill to put in place and are usually lubricated. Moving up the skill ladder you have EOA/EGTA (if those are still used these days - I'm remembering them for many years back). ET is the best by far, but those require even more training, practice, and skill. Not to mention that a laryngosocpe is typically used with them (although digital insertion is sometimes possible).

It's been ages since I taught, but I seem to remember oral airways being part of the basic CPR and/or first aid classes. Maybe I'm confusing that with EMT classes.