See https://www.wikidata.org/wiki/Wikidata:Property_proposal/numeric_ID:
An ID containing a string part and a numeric part. Usually the string may be changed but the numeric part never changes. One part may be missing though this is usually an issue that should be fixed.
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Open | None | T91505 [Epic] Adding new datatypes to Wikidata (tracking) | |||
| Open | None | T260639 New datatype for combined human-readable and numeric id |
I think it would help if the persistent ID is not solely limited to numeric values.
Although many websites use numeric values as their persistent IDs, others might use an alphanumeric string, a GUID or so on.
For instance, YouTube channel IDs look like UCBR8-60-B28hp2BmDPdntcQ (whereas the human-readable handle looks like @YouTube).