The post incorrectly claims you must pay by mail or phone. It also doesn't mention the security aspect of changing card numbers.

Whilst 1-3% cashback is may not be unusual in the US, ~0.2% is typical in the UK (maybe ~1% with Amex). Some countries have hardly even heard of cashback cards, I think. Looking e.g. here:

https://thepointsguy.com/guide/best-cash-back-cards/

suggests that the US market is also not as generous as commentors make out. Most high-cashback cards are quite specialised, often even changing month-to-month. There is only really one exception at 2% on all purchases.