When discussing Flash Sales there appears to be a lot of dislike in the hotel industry. The consensus could be summarized as that commissions of such email subscription promotional websites are way too high and discounts required are way too steep. Moreover you will be undercutting your own direct price positioning.
If your hotel runs at 95%+ occupancy each year, I of course might have to agree with you. However if your hotel is distressed or under-performing, you should look for opportunities to generate growth. From a revenue management perspective that is. Because in the end the cost of extra revenue is not extra cost!