While a simple "Hi," "Hello," or even "Hey" is appropriate in casual correspondence, a more formal salutation is appropriate when you are emailing about a business_related matter, such as a cover letter, letter of recommendation, or inquiry letter.
Nobody liked your project idea, so we are not going to give you any funding. The first version is a weaker statement, emphasizing facts not directly relevant to its point. The second version provides the information in a simple and direct manner. But you don’t need to be an expert on style to know that the first phrasing is diplomatic and respectful (even though it’s less concise) as compared with the second version, which is unnecessarily harsh and likely to provoke a negative reaction.