I’ve used this in several cases and wouldn’t consider it a bad practice. The WP title field has no way to insure that something like a unique product must be added. this can be done with ACF.
You can use the validate value hook to make sure a value is unique like outlined here https://support.advancedcustomfields.com/forums/topic/accept-only-unique-values/
and you can use acf save post hook to convert the fields into the post title, I posted an example of this here https://support.advancedcustomfields.com/forums/topic/delete-wp-title-and-use-acf-title/
