You will see the difference with YSlow and Google Page speed ranking but your visitors will thank you for providing a speedy website.
- If neither async or defer is present: The script is fetched and executed immediately, before the browser continues parsing the page
This will improve your global page loading time
However, this is not applicable to all scripts as you want to make sure the script is loaded while some other script or inline script will call it.
Perhaps your experience will be different.....I hope so.
I'm sorry to read you experienced issues.
This plugin requires some extensive understanding on the page rendering process to get significant improvements.
However if it does not fit your needs. You can safely uninstall it from the Joomla component manager.
Feel free to contact me directly by email at info - at - daycounts.com