Dbt over Bigquery

Hi dear dbt ( core and cloud) over Bigquery users

On the incremental official documentation) we can observe , both append and delete+insert incremental strategies are not supported
==> About incremental strategy | dbt Developer Hub

Do you know why ? Because it is working on my case
for a long time
No issues on Bigquery tables after a dbt build with incremental ==> append or delete+insert

Is it a bug on the documentation page <==an information problem or there are unknown problems ?

Thanks for any feedbacks