OK, but I would still prefer to take a quick trip to Malaysia than to go to the Immigration Department 3 times because apparently my papers are not enough for them. To each their own. I'm not doing that stupid extension process.
All nationalities are eligible for the DTV, at least I'm not aware of "restricted" nationalities, despite some phony websites claiming to list the "eligible passport countries". I know a guy from Ghana who got it and has entered without a problem via BKK. The official MFA website section about the DTV doesn't mention any restricted nationalities.
Of course she doesn't touch it, given the requirement is for the applicant to be outside TH to apply for it. The VAST majority of applicants don't need an agent for that.