WordPress Plugin vs Functions.php file (Which is better?)

We are often asked by users whether they should install a WordPress plugin or add code to their theme’s functions.php file? Some users believe that adding code is always the better method for performance, but that’s actually not true. In this article, we will explain the pros and cons of WordPress plugin vs functions.php file and which method is better. Installing WordPress Plugins vs Custom Code in Functions.php File
You will often find two solutions to add something to your WordPress site. You can either install a WordPress plugin or add a code snippet to your theme’s functions.php file.
Both methods will do the same thing, and they are both correct. However, many users want to know which one is better for WordPress speed and performance.
Some users feel concerned about installing too many plugins, and how it may affect their website speed and WordPress security. Others worry that adding custom code can break their website, and they may not be able to easily fix it.
Let’s compare both solutions to figure out which one is better for WordPress performance.
Pros and Cons of functions.php File
Functions file in WordPress allows theme developers to define custom
Source: https://managewp.org/articles/17388/wordpress-plugin-vs-functions-php-file-which-is-better

source https://williechiu40.wordpress.com/2018/05/03/wordpress-plugin-vs-functions-php-file-which-is-better/