When creating a keyword list using broad match, why should you leave out misspellings and plural forms of keywords?

When creating a keyword list using broad match, why should you leave out misspellings and plural forms of keywords?

• AdWords only shows an ad for keywords with proper spelling and plural forms
• Your keyword list would be disapproved based on Google’s advertising policies
• AdWords can automatically include these variations for you
• Broad match includes the exact words and phrases a user searches for