Lightspeed is very well crafted in a way that if you don’t have the knowledge of coding, you can just install a theme and use the settings to customize. Theme builders like us can make sure your theme stays updated by modifying parts of the source code to that sealed package when needed.
Once you decide to activate the template editor, you have full control over the source code, and can make your own changes. However, the updates from the theme developer won’t be installed automatically any longer. This makes sense because in theory, we would be able to override or break the code you’ve just created.