Functional resumes highlight your skills and abilities, such as hiring, managing, or coaching, rather than your chronological work history.

Functional resumes require more time from recruiters

It is much easier for your eyes to scan and read materials that follow the same format.  Recruiters read hundreds of resumes a day. They usually only spend a few seconds scanning each resume. Most resumes follow the traditional chronological layout, and recruiters can easily scan them to find the information they are looking for. If your resume requires more time to find the relevant information, you have better caught the recruiter’s attention, in a positive way, and given them a reason to decide to invest more time reading yours.

Where are the red flags?

Recruiters and hiring managers look for red flags in the resumes attempting to identify areas of concern. Unexplained employment gaps and job hopping tendencies are red flags that recruiters look for. Information about these is hard to find in a functional resume, especially if it does not include the candidate’s chronological employment history.

Instead of using a functional resume add a skills section to your chronological resume

My recommendation is to not use a functional resume, but rather add a skills section to the top of your chronological resume. Make sure to include in this section key words from the job description, to get your resume through the ATS.