Amex Plat offer – any downside to dropping charge for a (wife’s) credit?

[AGR]

Is there any benefit to staying on the old Amex Plat card instead of the new (charge card versus CC)? We’re Considering taking out the latest Amex plat offer for my Wife, and later cancelling my existing one. In principal this should capture the offer Avios etc, but maybe there is a drawback?

[BuildBackBetter]

Charge cards have two major advantages. You can add more free supplementary cards (only one free plat supp though), so you can get multiple gold cards if you want to track expenses separately or dislike carrying the metal card. Second, the credit utilisation in your credit profile appears slightly better as the limit is very high. Rob had an article on the differences if you want more details.

[Gary_Dexter]

BuildBackBetter wrote:

Charge cards have two major advantages. You can add more free supplementary cards (only one free plat supp though), so you can get multiple gold cards if you want to track expenses separately or dislike carrying the metal card.

You can’t add yourself as a supplementary card user though to achieve this, right?