There is a feature on vendor invoices that you can auto-complete them from an outstanding purchase order. This is very convenient to quickly enter purchase lines on vendor invoices in the accounting module.

I also have outstanding sale orders I hoped to use a similar auto-complete feature while creating customer invoices, but I don't see this. The only way I found to create customer invoices related to sale orders is to start from the sale order itself.

Am I missing something ? Or is there a reason this is only available for vendor invoices ?

I'm seeing the same behaviour in both odoo 13 and 15.