For a one- or two-day rental, getting 1,250 AA miles for $1 or $2 +tax is a no-brainer. But for longer rentals, do you earn extra rental credits with some companies based on length of rental?
Also, if you need LPs, you will get them by crediting rentals to AA. Whether all 1,250 miles will count as LPs, or only the base 500 miles, is something I don't know -- yet.
How much value do you typically get from your AA miles? I just redeemed 7,000 AA miles + $5.60 for a May domestic one-way in Economy for which AA was asking $383. (But I do not expect to get 5.4¢/AA mile on a typical redemption.)