Seems to me OP thinks it is passenger’s choice on which option is to be provided when it is actually airline’s choice.
AA allows for reservation to be held. If passenger does not take advantage of this hold, AA is not required to (but not prohibited from) providing the alternative option of 24 hour cancel after ticketing.
14 CFR 259.5(b)(4)
(4) Allowing reservations to be held at the quoted fare without payment, or cancelled without penalty, for at least twenty-four hours after the reservation is made if the reservation is made one week or more prior to a flight's departure;