It's a funny video and it reminds people that they have civic duty to vote. Anything that people do to remind people to vote who might not otherwise be thinking about it can help to increase voter turnout. It's also a great reminder that voting is easy and it does not require lots of ceremony.
It will appeal to her audience, because she has the crowd their to convice with her stage and past achievemt, If she can buttress her opinion with a straight forward approach, not only telling them through video but mentioning the benefits of casting their vote would more or less draw her crowd. And also, she is a celebrity, so is a good platform to add more ego.
Madonna, who has been very supportive on Twitter lately, is also pro-naked voting. She shared this NSFW, yet still modest-as-far-as-nudes-go pic wearing jewelry, a grill, and not much else while pledging her allegiance to Democratic candidate Hillary Clinton.
I don't know if it will really encourage people to vote, but anything's worth a try. Voter apathy is not a good thing, and even though most people either take it for granted or don't know how the system really works, it's always a good thing to try to encourage voter participation.
Taking one's clothes off to encourage voting for a candidate is ridiculous. There is no real connection between the two subjects. In addition, these two women are liberals and conservatives know this. It might encourage conservatives to vote republican just for spite, but it isn't going to change how voters believe inside.