In the above article, it mentioned "worldwide" but since the receiver still has to use Strike, then that defeats its purpose to a large extent [at least until they integrate it with something else]!
Strike was there in the testing phase and it makes sense to be the first live, especially as it looks a bit rushed (only iOS?
). Strike is not only limited to certain countries, it's also KYC, hence not so appealing for bitcoiners.
But it was said that Twitter tips will use other LN solutions too, even non-custodial ones, when the Bitcoin tipping goes live, but I guess that it'll take time. A good list is here:
They mention using Blue Wallet, Wallet of Satoshi as LN custodial wallets and Breez, Muun, Phoenix and Zap as non-custodial wallets, so there are plans to add other options for tips maybe even upcoming Square hardware.