> If you knew enough about RNW to look out for sites using it and pose a question about it then I assumed you knew enough about Flutter to do the same?

That it exists, it's general purpose, and given it's semantic version that it's pre-release software. That's all I know about it. I know a little more about Flutter since it has a marketing budget.

It probably wouldn't be wise to rely on either of them outside of hobby projects. Unless of course you are Facebook/Twitter/Google, aka have effectively unlimited budget and employ the people who wrote the stuff to begin with.