You want your WordPress site to load as fast as possible for your site visitors and if you have a plugin installed that negatively affects your site's performance, then you're going to want to know about it and fix it as soon as possible. I used to recommend a plugin named P3, which stood for Plugin Performance Profiler. That plugin would help troubleshoot this very issue. Well, the P3 plugin has not been updated in several years and will not even work on sites using the current version of PHP 7. Which by the way, is what every WordPress site should be running on.