The Firebase team also explains in a now 6 year old video (https://youtu.be/Elg2zDVIcLo?t=276) that the main value of reference types is in the Firebase console UI.
It is stated that if a field is set to a reference type, when editing the field you will get a rich editor allowing you to select another document instead of just typing an arbitrary string which would be prone to mistakes or referencing non-existent documents.
Unfortunately that feature still doesn't exist. And since the feature to filter documents based on a reference field is also missing from the Firebase console, reference fields seem to serve no purpose and provide no additional value compared to using a string id pointing to another document.
The Firebase team also explains in a now 6 year old video (https://youtu.be/Elg2zDVIcLo?t=276) that the main value of reference types is in the Firebase console UI.
It is stated that if a field is set to a reference type, when editing the field you will get a rich editor allowing you to select another document instead of just typing an arbitrary string which would be prone to mistakes or referencing non-existent documents.
Unfortunately that feature still doesn't exist. And since the feature to filter documents based on a reference field is also missing from the Firebase console, reference fields seem to serve no purpose and provide no additional value compared to using a string id pointing to another document.