No! It is not necessary to use rewriting tool. It is designed for the people with poor English to fulfill their needs. If you are a professional content writer, then it’s also useful for you. It will enable you to increase your vocabulary and synonyms memory. Recently, we have added up to 500,000 synonyms in this tool for english language and it will enable you to create content with more professionally.
From personal experience Spin Rewriter is the best! like I still use it today. Its so easy to use (Just copy paste and the program do everything) Because of this tool I managed to schedule content and articles for 3 years, do you know how much time and money I’ve saved?!?! A LOT!!! Also i high recommend you pick their mothly plan if you are still in doubt