Livre d'Or

I could off the top of my head name half a dozen elastomeric respirator users I know personally who have had Covid. Certainly the never-Covid portion of my acquaintance over-represents people taking this precaution, but it's still not a magic talisman. And maybe they didn't wear the elastomeric properly, or took it off in an inappropriate / unlucky situation; most people don't know the exact moment when they caught Covid.

Lab evidence indicates that an elastomeric mask isn't that much better than an FFP3 / N95. I would predict that the main difference in practice is that elastomerics are more comfortable to wear so people are more likely to actually wear them all the time they're needed. I would find it plausible that it's somewhat easier to wear a rigid half-face mask ideally, with a good fit, than a disposable mask, so the elastomerics may be better for that reason. But we're unlikely to get clear real-world evidence on that because as you say, it's tiny numbers of people who wear elastomerics consistently, and they're generally very cautious in other ways.

I do think that the kind of evidence looked at in the Cochrane review is important, because if it turns out that telling people to 'wear a mask' means most people wear the wrong kind, or wear it inconsistently, or intentionally refuse to follow the advice / mandate, that itself is useful data. But it's not relevant to whether I personally should wear the best mask available to me.