Personally I think it comes down to what you want to get out of it and the relative costs. Obviously you are not interested in working, but I think its fair to say that a significant proportion of candidates that enroll in the DM programme are in the same position.
Many travellers on gap years and career breaks use the course as a way to get in a bunch of cheap dives, and also as way of adding an additional professional accreditation for their resume that shows that even if they did take some time of to travel/'find themselves'/whatever, they weren't just being a beach bum. The other advantage of the DM is that you learn a lot more about diving science and theory, increase your own personal skill level, and generally become a safer and much more aware diver (although to be fair I'd say the rescue course also does the latter better than any other course on the market).
So how much does that set of benefits matter to you? If the answer is not greatly, then it comes down to cost. Since you mentioned Thailand, I'l break it down for you in terms of what your money would get you here (we're based on Koh Tao in the Gulf). The DM course with us costs 30,000THB, plus 6,000THB for your materials. For this you get all of your training, workshops, assists etc and unlimited fun diving for the duration of the course. The same money used towards fun dives would get you somewhere between 40-50 dives depending on the dive sites. Most of our DM candidates stay for 6weeks - 12 weeks. Lets say on average they do a 2 dive trip 5 days a week (taking into account illness, injury, down time, visa trips etc) either as fun dives or part of their DM. Thats between 60 and 120 dives they are getting for the same price as 40-50 fun dives, plus the certification at the end. So from a financial point of view, there's no denying it is good value.
Before you make your decision, bear in mind that the DM is not all about fun diving though - although in most programmes it's arranged so that you get a fair amount of that too. A significant proportion of the course is dedicated to a combination of academic learning, skills training, assisting and workshops. So it really comes down to what your priorities are - ie whether you are willing to compromise on sacrificing some of your fun diving to complete these aspects of the course in order to get an overall better value deal.
Good luck in your decision. And happpy diving
