In my opinion, it provides credibility for employers that you are making an effort to learn more beyond the bare minimum as a clinical pharmacist. In the sense of applying for jobs, if two candidates said on their resume that they were motivated to learn and provide value to improve patient outcomes, they'd most likely take credibility towards the one with the BCPS.
Also it is a pain in the butt but the large of amount of CEs that you have to complete to recertify keeps you up to date with useful information that you have to do rather than do BS CEs that you choose to do just because its easy.