No. Musing.io has been clear from the very beginning that their upvotes are always based on the quality of questions and answers given, and nothing else. That is explicitly stated in their Curation Guidelines.
A quality answer will always trump a long answer. With that being said, if there are two answers that are both of quality, but one is longer and more detailed, then it is possible for the longer and more detailed answer to get a higher upvote. Why? Because the longer answer might be more in-depth, it might be more informative, and it might feature additional examples.
It's important to understand that all these factors--depth, completeness, and the level of details, add to the quality of the answer. Sure, they also add to the word count, but that's just a consequence of the quality answer. It wasn't a quality answer because it was long. Being long was just an add-on. That's assuming, however, that the long answer was not rambling and stuffing words to be longer. Because if that were the case, then the longer answer is just fluff, and that's not quality.
So, does word count matter more than quality? Definitely not. Quality will always trump everything else. That said, if you think you can improve an answer by making it longer, then don't hesitate to make it longer. And if you think you're rambling, then edit and make your answer shorter. After all, your goal shouldn't be whether to give a long or short answer, it's to give the best one.
Source:
Musing.io Curation Guidelines. https://docs.google.com/document/d/1WKYGhdPhLKNHytsxAPPQiXyv5UBY6nUKM8IhG5PUgfA/edit