The more Spanish you look, the better looking, professional, educated, smart, wealthy, etc Mexicans assume you are.
A very racist culture.
I remember when my ex tried to talk to our “el Indio” gardener (once every other weekend to mow the lawn and trim the hedges) in Spanish, he looked at her strangely and said “I don't speak Spanish”. He spoke English and his native Amindian language. Had no interest in learning Spanish and didn't much care for Mexico or Mexican culture.
Can't say as how I blame him.