Hi xcjy
This is an "experimental feature" that needs to be enabled manually from WC settings.
And, as WooCommerce says in that section:
"These features are either experimental or incomplete, enable them at your own risk!"
We cannot add support for something that is incomplete or subject to changes. When they are 100% stable and we are sure they are going to be moved to core, we will support them.
We've seen in the past many experimental features that were finally abandoned...
Best Regards,
Salva.
