As a matter of fact, the study itself seems to provide a positive result that, ironically, authors have used to discredit similar studies
That said, from personal experience (as someone who lost 60 lbs by making changes to my diet) chocolate does have beneficial effect on weight loss, in that at a very least consuming smaller amounts of chocolate (in terms of calories) satisfies craving for sweets better than consuming much larger (in terms of calories) amount of other sweet foods (such as pastries). Just this benefit alone is sufficient to recommend (prudent) use of chocolate in a calorie-controlled diet.
As far as "bitter chocolate tasting bad" - well, tastes differ and some people find caviar or foie gras to be disgusting, but by an large they are smart enough to keep those opinions out of research papers. Me - I'll take my 90% dark any day (but don't shy away from milk chocolate, as long as it's not Hershey's anyway)