I dunno. I know people who use their Memojis regularly and seem to enjoy it. I personally do not, but I think I’m not their target user. Not sure what the broader adoption looks like.
But I think these are different enough capabilities that the success or failure of one is not necessarily predictive of the other.
As a method of estimating adoption, that seems fairly suspect. It doesn't exactly seem like a capability that would generate much news.
Google Trends seems more likely to be instructive, and as a topic, it has shown fairly steady (if low) interest over time after peaking on release with some periodic spikes most likely correlated with major updates.
But as a feature, I wouldn't expect even Google trends to be very instructive (for understanding adoption), since people who know how to use them aren't likely to be out there searching. More use = more familiarity = less searching. Who knows; maybe they're barely used, but there isn't good data to back up that claim, and there are a number of other ways to interpret the data that does exist.
With all of that said, I'll maintain that I don't see any real connection between them and Personas, or any predictive value in comparing them.
Uh, of the 100 or so acquaintances I have who use iphones, way more than half of them use their memoji for their public-facing visual representation. Nobody writes news articles about that for the same reason they no longer write news articles about the ability to use your voice to dictate messages, or charge your phone without plugging in a cable.
But I think these are different enough capabilities that the success or failure of one is not necessarily predictive of the other.