Because you speak English, would you like to be mistaken for a Canadian instead of an American? Probably not!
It's savvy management for employers to know which countries their employees come from.
Good manners are a sign of solid upbringing.
Etiquette is so important on the job many think "por favor" and "gracias" are the two most important phrases in the Spanish language. This will help you build trusting relationships that Latinos value. It's almost like carrying a cell phone. When we see a person speaking Spanish, many automatically assume that the person is Mexican. In a Latin American's eyes it's rude to "cut to the chase" on tilting pad bearing the telephone and immediately begin to discuss business without first asking how the person is that you are talking to. This is true for both first and second generation Hispanic employees.