Should you, small or medium size the restaurant owner or manager, do something similar to compete with these chains? The short answer is NO, you shouldn’t, and I will tell you why.
Your marketing goal should always be to convert prospects, and occasional customers, into long term repeated clients. Anything that you do towards this goal is good, and it moves you in the right direction. Anything else will make you waste money or just attract customers who are probably just interested in getting the cheapest meal they can get anywhere without any loyalty to a specific restaurant.
Giving away meals to attract people without a long term vision or marketing goal is not a wise strategy. Yes, you may get lots of people going to your restaurant to take advantage of the free food, but this doesn’t mean you will make any profit, or that they will become future clients of your restaurant. What you should do instead is to implement a formalized referral system, where you select your best clients and give them special gift certificates that they can share with their friends and families. In this way, although you are giving away important discounts, you are doing it with a purpose: to bring new prospects to your restaurant. To bring quality people who have been recommended by their friends or family members. If you follow this strategy your restaurant will also gain instantaneous credibility, since people believe more the recommendations of people whom they appreciate and trust than any other form of advertising.
You should always have a long term marketing strategy instead of trying to jump into whatever marketing trend is fashionable presently. In this way, you will know the direction and the final destination where you want to take your restaurant. Yes, your circumstances and the economic reality can change, and you may follow different roads to reach your destination, depending of your needs, but if you have a master plan, a strategy, and a vision, you know that you will be going in the right direction, and eventually you will reach your goal.