[notahacker]

Any cc processor has to worry about age restricted products or services using "Enter your credit card details here" to do their ID checks, especially since that is often combined with dark patterns that downplay the fact there's a charge associated with that. And age-restricted products tend to come with a whole host of other liability issues which they probably don't want connected to Stripe-registered US shell companies.

[superuser2]

It also doesn't make that much sense, considering that 15-17 year olds are regularly issued debit cards for checking accounts (though the parent is also usually a joint account owner). AFAIK nothing in the Visa/MC network has "Birthdate" field.