A huge part of how we interact with the world (and the internet) is through shared mental models. It's easier to understand something if it works in the same (or a similar) way as other places we've encountered it. Nielsen, (the god of web usability heuristics) makes the point that people spend most of their time on websites *other than yours*. Jakobs Law means that users will prefer your site to work the same way as all the other sites they already know. This is why so many website look the same – it's not (always) because people lack creativity – making them too different can make them harder to use...and therefore affect conversions/usage/revenue.
This approach to design is why you can jump into basically any car, anywhere in the world and understand how to drive it. It's also why the design of door handles on Tesla's is problematic, and why you have a hard time adjusting to countries where they drive on the other side of the road.
Let's shelve "the web is getting boring" convo for now.
So, how does this relate to Twitter? Well, the blue checkmark has meant (more or less) one thing for over a decade. You can argue about how it was given out, and to who, but generally it's understood to carry a sense of trust and 'verification'. It's a design element that is well understood and repeated across other widely used social networks – always with the same/similar meaning.
Suddenly, Elon Musk decided to completely change what the blue check means and make it a paid feature, rather than being tied to verification. Naturally, this is confusing since it means something different everywhere else and has for a long time. This also means Twitter has to add the new 'gray check' to compensate for that change and handle the concept of "verification
TLDR; It's confusing because we're used to it meaning one thing, and now it doesn't. I empathize with the design team, because they're likely trying to make the best of a bunch of untenable demands and 'good enough' solutions in a short timeframe.
Edit
Whelp, Elon has now removed the "Official" check less than 24 hours after release. Doesn't change the issue with blue check meaning.
Edit, again
Ok, so now we're back to just the blue checkmark but it still can mean two very different things. As a *new* solve, you can tap or click the icon to show whether this IDENTICAL UI element means one of two things.
Also, this is amazing.