Using Cloudflare Analytics and auto vs manual setup?

If we are proxying a site through Cloudflare, there is the option to setup two ways to implement Analytics:

Select a hostname from the drop-down menu. Automatic setup is enabled by default. To set up Web Analytics manually:

    1. Expand Advanced options.*
    1. Select Disable automatic setup.*
    1. Copy the JS snippet.*
    1. Add the JS snippet to any of your website’s HTML pages before the ending body tag.*

Why would I use adding the JS snippet manually over leaving it in Auto setup mode - any advantages/disadvantages?

Thanks

Simon

Automatic only works with orange-clouded traffic (proxied through Cloudflare)