The cards that full frame cameras use to hit 800mbps are CF not SD. Functionally very similar, but you can’t just pop it in your laptop. You need an external reader. The nice thing about SD catching up to the CF spec is backwards compatibility. You can take your 800mbps SD Express and throw it in your laptop’s SD card slot and use it, even if it’s only at 100mbps because the laptop still uses an old SD version. No such luck with CF Express unless they can convince people to build CF ports into laptops and phones (though SD is just about dead in phones).

It basically means trend. It’s sorta evolved from the concept of “metagaming” where you’re not just playing the game, you’re gaming the game. People now use “the meta” to refer to the collection of viable strategies for a game, and “the current meta” to refer to what is popular at this moment. This could be types of decks in a card game, character builds in an MMO or a MOBA, or other things like that. Presumably, for twitch, “the meta” is referring to not strategies of playing games, but strategies of gaming twitch. In other words, strategies to maximize viewership and income, and specifically, what is working at any given time.