I've read papers showing health benefits of 3 or 5-day total or buffered fasts. The results of this particular scheme look promising for health, but IIRC the study size was only 19 participants.
From many IF research papers, it seems that extended fasts, every 1-3 months probably have health benefits. However, being cautious I'd suggest checking with your doctor before any fast longer than 3 days: these longer fasts are normally under supervision and I personally wouldn't attempt this on my own.
So, FMD is not for me, but there are some quite keen fasters on these threads who might have a go < B&W: be careful and talk to your GP first ! >
As regards weight loss, FMD should work well for someone who naturally eats the correct amount for their body - studies always seem to use such people.
However, in the real world, someone who tends to significantly overeat might not lose weight, or might even gain weight, if they eat what they want 25-26 consecutive days per month. Many folk who've managed 2 or 3 FDs during the week then eat / drink back the entire FD deficit and more at the weekend.
So, I wouldn't take to literally the idea that the non-fast days are completely unrestricted, unless you are confident your eating is already sensible.