According to wikipedia ...
In reality, aniline is a clear and transparent chemical that allows the grain structure of the leather to be seen. It has nothing to do with protecting leather from damage or hiding it.
A full aniline dye is one method of tanning to achieve a desired, natural looking hide or leather. Semi-aniline utilizes aniline and other chemicals to get different looking finishes. A very appropriate analogy is the difference between a semi-gloss and satin paint finish. Neither is better or higher quality than the other. Different chemicals are used to achieve different finishes.
But now I'm curious. Where did you find information that confirms that Novillo leather is aniline. I cannot find out much on the Internet about "Novillo" leather.