Hi @strobley,
I’m checking this issue and font-awesome is the only icon library that the builder and theme have, there is nothing to fall back to when it’s disabled, those icons will remain empty even if the dependency is removed. Like the add-to-cart icon, there is no other add-cart icon beside the one from font-awesome. And the removal of ajax or other functionalities relying on icons will greatly affect user experiences and integration, like with other plugin’s features (like Woocommerce ajax cart which primarily a shop feature/setting).

That option to disable font-awesome is only given so the user could include their own icons through custom CSS, and with the help of 3rd party icon libraries. The missing icons are visible so user could follow which needs the icon replacement. For example, let’s say you choose an image as an icon.
.x-icon-angle-down:before,
.x-icon-angle-down::before {
content: url('//example.com/some-image-scroll-down.jpg');
}
If a user isn’t gonna add or implement their own icons then I don’t recommend offloading the font awesome icons through that option, the icons are mandatory for some graphical controls.
Perhaps you wanted to apply your own graphics? We may able to assist you by providing more ideas how it can be done. But we can’t fully provide the customization for all the icons.
Thanks!