It is best used at the very beginning of any campaign or design process as a discovery tool to help get everyone aligned and ‘on the same page’ and, importantly, to uncover insights about how your customers think.
It cannot be done in isolation.
It needs everyone with ‘intelligence’ on the customer(s) to come together to help build a strong picture - so Marketing, Sales, Customer Success, C-suite, etc.
We also recommend you add first and third-party research, survey results, testimonials, customer interviews, competitor insight, etc. to help fill in the gaps.
We’d also recommend doing an Empathy Map for all key members of the buying committee or group that you are looking to influence.