It may very well be important in a business setting but... I know some very successful people whose grammar is poor despite the fact that they have degrees from fine schools. What they possess (in addition to business skills) is the ability to communicate.

I could have some fun grading that sentence
I have a cousin who teaches English at a school for exceptional students. We come from a poor white trash background. She never corrects nor makes fun of the way our relatives back home speak. I respect and admire her for that.
I have an eighth grade education. I have friends with advanced degrees including a couple of PhD's. I also have friends who didn't finish high school and wouldn't know a comma from an apostrophe... but they are intelligent and interesting conversationalists. Like I said before, communication and content are much more important to me than correct grammar and clean syntax. If I can understand what someone is saying, and what they are saying is interesting, I don't care how they say it.
Sorry but life is just too short to sweat the small stuff.