Having watched this debate play out, I think there seems to be one major misconception regarding masks. They are not and never were meant to be the sole means to attempt to slow the spread of the virus. They are meant to be combined with other safety measures, specifically hand hygiene. So yes, it is true that people can't wear them 100% of the time and people will no doubt contaminate them or use them improperly. They aren't a substitute for other measures. They're meant to be one part of the solution. But the bottom line is that this is a respiratory virus that is spread through coughing, sneezing, and just talking. A face covering that reduces the spread into the open air is certainly helpful. If you knew you were going to be trapped in a room with someone with known COVID-19 and you had the option of having them wear a mask or not, what would you choose?
The question of whether or not you want to go to Disney wearing one is completely subjective. The question of their effectiveness is, however, backed by scientific study.