Quick Question about Data Removed if Uninstalled

Your plugin has this as an option:
Remove all plugin data on uninstall
only applies when the plugin is deleted via the plugins menu

My concern / question is obviously the plugin would be removed, but I’m wondering about the “data”. If one chose to NOT remove data upon uninstall, just what data stays behind?

http://ww.wp.xz.cn/plugins/allow-php-in-posts-and-pages/