To have a Xingyi master for a wife, I am sure Master Meng had to have some skills to impress her for marriage and be safe during personal arguments
Black Tiger system seems to be a really no-nonsense, brutal and direct martial art descending from the Shaolin temple, which unfortunately suffered the loss of reputation due to secrecy and the popularization of other internal arts.
From what I understood of the bio of Master Meng, he learned only Four forms of the system for the first 10 years!! And completed another four forms after learning the Tongbei system. I somehow always feel that the more covert the art is, the more goods it possesses.