Functional format is best for those who are switching their career or have large employment gaps on their resume. In this format, you dont have to list the joining or resigning dates of the previous employments. Functional format will hide your employment gaps or your job switching.
Your resume is your marketing tool for success. You need to be able to advertise your skills and ability to succeed with your prospective employer. The format and feel of your resume can either open doors or close them often this feeling can make people question why they didnt get the interview or thinking they are not qualified.
In-all a good template makes the resume stand out from the crowd a raw template made before-hand saves your time when you need to make some quick changes or wish to make the resume target a specific job opportunity and is appealing. So in a world where looks have the power to hide the content why not take the benefit?