Can I second this - I’m building an Inventory / Sales recording app for a client at the moment and would really like to be able to add the sales items in a more intuitive way. Whilst you can record them through expanded view it gives you the primary option to link to existing records from the sub table. Now, in this type of use case, I can NEVER see when this would be the correct choice - yet users are almost encouraged to do this. Furthermore, if they do select an existing record (which by definition belongs to another sale), the database will create a link to the record - despite the sales item table being set to only link to one parent record.
This leads to incorrect and meaningless data.
What I would like to see is that Airtable should be able to be configured so that the link field only gives you the option to enter NEW records (or view/edit existing child records) - and this should be the default behaviour on the ONE side of a One to Many relationship. This would make data entry of this type into expanded views quite usable.