Is using wp_enqueue_script necessary?

Is it necessary to either register or to load scripts using wp_enqueue_script() or would there otherwise be an advantage to using wp_enqueue_script() if the scripts are all proprietary (no chance of conflict)?

The current technique I’m using is to load these scripts in the page footer. The main page template loads the appropriate footer which, in turn, loads the required JavaScript by passing the footer’s slug to the get_footer() function.

I can detect no problems with this approach.

(I’ve read some of the answers on this forum about loading specific JavaScript files on specific pages and all the answers seem to make it unnecessarily complex.)

Thank you.