This article is completely false. User balances are held as USDT. It's powered by Bitcoin and ⚡️, not by USDT. Users can send/receive onchain or on ⚡️ just like all other Strike users. Jack has explained how Strike works many times. https://bitcoinmagazine.com/business/jack-mallers-strike-bitcoin-agility

bitcoin.com is probably the worst source to get information about Bitcoin. Be careful there, it will try to trick you into one of the failed forks...