Only watch if you want a negative example of just how insulting old Hollywood could get. Contrary to the other reviews, minstrel and blackface was going strong until the 1950s and even made its way onto TV, until civil rights protests put an end to it. There was even blackface in films into the 1980s, Soul Man and Trading Places. (Yes, Tropical Thunder much later. But that was criticizing and mocking the practice of clueless whites portraying other races.)
The music is terrible and the comedy is far worse. Blackface was half imitating Black culture and half mocking Black people. But here the music is corny and tone deaf.
Blackface makeup can be incredibly jarring to see, to be reminded of just how deep racist hatred went to dehumanize Blacks. Here the mockery is also of Blacks who would dare to dress well or have money, for the clothes are over the top too.
Only see if you have a strong stomach and have a historical interest in Hollywood stereotypes.