I don't understand the integration with Strike at all.
Why not implement the tipping feature in a way that works with any wallet (including, but not limited to Strike)?
I can only assume it's something to do with Twitter being a US-based entity, maybe? The only way it makes sense in my head for them to knowingly restrict usage to the US and El Salvador is if some regulator/lawyer/other-red-tape-dispensing-bureaucrat has advised them to.
It's likely they don't want to end up facing (likely baseless) accusations of aiding money laundering, so they're going down the route that involves at least some KYC/AML.
I was about to even question why the need for invoicing and such, and then yes, I just remembered Twitter's quite uncompromisingly a US entity. That's when all this complications made sense.
But then, doesn't (or didn't) Reddit -- also a US company -- allow Bitcoin and crypto tipping? Didn't they have a tipping bot that didn't even interact on-chain until you withdrew?