Amex charges merchants a higher (%) fee which enables them to give more back to consumers in rewards. "Packaged accounts" usually come with a monthly fee to provide additional services.
For the consumer they are either a very good thing, or a very bad thing; there's usually no middle ground, as described by an analyst at MoneySavingExpert.com,
"Used well, these accounts can save you around £500 a year compared with buying all the insurances they provide separately.
"But, if you can't or don't use the benefits, then they're a colossal waste of money. If you have, or get, a packaged account, always make sure it'll save you, not cost you."
Martin Lewis describes packaged bank accounts as the Marmite of banking!
"their nature means they're a paradox. If you're one of the millions who have, or had, a fee dripping from their account each month, check now if you're being diddled. If you're on a fee–free deal, check now whether you'd be better off paying."
If Monzo ever decide to go down the packaged route, they will need to tread carefully. Packaged accounts are the subject of more complaints than any other financial product, bar payment protection insurance (PPI). One way to avoid this dissatisfaction would be help consumers carry out checks beforehand to confirm a net financial gain with a package.