Originally Posted by
USirritated
I have thought about this a couple of times when I am points heavy and miles poor, but have not done it as of yet. Are there any repercussions that might not be obvious about doing that switch and then switch back?
If there's a Megabonus going on, I think you might have to have your earning preference set to points to participate (not sure).
You earn miles at a much lower rate than Marriott points. For American, it's 2 miles/dollar at FS hotels and 1 mile/dollar at CY, FI, RI, etc.
I know this is thinking longer term (and in large numbers), but:
Even assuming you're staying at 100% full service hotels, you would need to spend $60,000 on room rate to earn 120k AA miles. For that same $60k in room rate, you could have earned 900,000 Marriott rewards points. For that 900k Marriott points, you could convert three cat 5 travel packages, giving you 120k AA miles each. Even throwing away three(!) 7 night Cat 5 certificates, you'd still have 240k more AA miles by crediting Marriott points, and then converting (not including Megabonuses). And you'd still have 90k Marriott points left over.
Obviously, this is the worst case scenario, but I think it holds true for smaller numbers.
ETA: I was a little slow, and
hhoope01 beat me to the point.