I would expect a client to want me to use SEO software to gain an advantage for them. Customers or clients will not want you to be guessing at their SEO and marketing, they want results. If you can gain an edge and get amazing organic results then you are on a winner. Remember to set up your Google Analytics or similar analytics package to monitor conversions and check on how well your improvements are doing.Website design and web development should be designed with users and optimizing in mind, much of this data comes from tools and connected 3rd party API.