Aside from being able to edit files without the Template Manager – is there any advantage to saving templates as files in ExpressionEngine?
Is that increase or decrease website speed? Does it improve performance, security, etc.?
Frm where website takes that page template file or database?
Don’t Save template as file – saving templates as files can marginally increase disk i/o as each template must be retrieved from disk in addition to the standard database query
No, that's the whole point, being able to edit files via an external editor. Should the db and the file version be out of sync, EE will use the file.
Theoretically disc i/o should be slightly slower than a db query, but it rarely matters in practice unless we are talking about really busy sites. With template caching enabled the difference should be close to nil.
To check it, enable the template debugger (CP Home -> Administration -> Output and Debugging Preferences) and look for "Retrieving Template from File" on the debugger section of the rendered template.
Please consider the following answer:
Pros
Editing through your favorite editor -> faster
Enables you to version your files with a VCS
You can DIFF files
Easier to maintain code markup/layout
Cons
Slightly slower because EE needs to check the files for a new version (i guess it only uses the file versions in the latest EE releases).
Could be a lot slower on a provider with a slow file system.
Synchronization hassle
