Templates are a major time_saver: The most obvious benefit of using a template is that it's a major time_saver. You don't have to create everything from scratch because a lot of the complex work is done fore you. A template allows you to drop in the look you want and then customise according to your needs. This is significantly faster than starting from a blank canvas. Templates can give you a competitive advantage: When you manage projects and delivery it successfully, it's essentially competing with other project managers, departments or against another company.
When you are writing your proposal, attention to detail is very important. You must write everything in clear and concise English. You should never use slang and only use the technical terms that you must use. The person who is reading your proposal may be a lay person and become confused if you use too many technical terms or job related slang words and phrases. Color for your graphs and charts is quite acceptable and as it eye catching can mean the difference between submitting a wining proposal and one that ended up in the "also ran" file.