I came to the conclusion many years ago that earning miles through Marriott rewards was not the best return on my money spent. For example:

If I earn miles and have spent $20000 at full service Marriotts over then past couple years then I would have earned 40,000 miles in my favorite airlines program (in my case AA) and 1 mile per dollar charged, or an additional 20,000 miles, assuming one has a mileage earning CC in the same program. Total of 60,000 miles.

If on the other hand I had chosen points I would have earned 340,000 points ($20000 x 10=200,000 + 20% silver bonus 40,000 + 5 points per dollar spent for using MR Premier VISA 100,000). More if one is Gold or Platinum. Also many bonus promotions only apply to those earning points, Winter Double Points promo (last year) I earned another 100,000, and the Spring Promo I earned 30,000 points. But even not counting those bonus points, for the 340,000 points I can get a week at a category 6 Hotel, plus 120,000 AA miles by cashing in a 250,000 points for a travel package and I would still have 90,000 MR points left over. Since a week at a Category 6 usually runs 130,000 points, that means I just swapped 120,000 (250,000 points for travel package less 130,000 points for the free week award) MR points for 120,000 AA miles, a 1 for 1 exchange. So reducing this to comparable currency, by earning points it basically translates to a net of 90,000 points, a free week at a category 6 Marriott, and 120,000 miles which is more than double the earning power under the miles earning preference of 60,000 miles (40,000 miles and 20,000 miles from a CC).

On top of that, there was a promotion at American Airlines that ended on May 31 last year that gave a 20% bonus in points transferred from Marriott Rewards, so I got 144,000 AA miles for my 120,000 Marriott Reward points. With the double point and mega bonus point promos, my Platinum elite status bonus points, and AA points transfers bonus (if it comes around again) the comparison for me would be more like 240,000 points, a free week at the Vail Marriott, AND 144,000 AA miles as compare to 40,000 miles and 20,000 miles from a CC. A huge difference IMO.

My recommendation is to make your earning preference points, the rate of return is much better.