Using a functional resume format is beneficial when you have gaps in employment. The functional resume highlights honors and achievements more than work experience. It lists your skills and other attributes that make you a good employee at the top of the resume. It is important to fill the gaps in employment with experiences that helped you grow. Volunteer work, continuing education, and other projects you worked on during that time are all great options. Be sure to use a positive tone while describing the gaps in employment and be confident about them when interviewing later.
In addition, functional or combination resumes may also be useful if you are trying to draw the readers attention away from something – namely, large gaps in your work history or detours into unrelated fields.