They take up disk space and resources
SiteGround Security Optimizer – The All-in-One WordPress Security Plugin
With over 50,000 plugins in the repository, it’s clear that WordPress plugins are an essential element for any WordPress site. You’ve probably tested and tried many of them to solve problems or perform tasks. If you decide you don’t want to use them anymore or they don’t work as expected, simply deactivate them and then remove them from your WP dashboard.
However, this will not remove all traces of a WP plugin and will leave rows and tables in your WP database.
The plugins most likely to store data include form, caching, security, and SEO plugins. Before proceeding, you should backup your website in case something goes wrong.
