The interface with Salesforce allows you to Create new records in any Salesforce object, including Customs Objects. It is not limited to the management of Tasks or Incidents.
In Jira, we can use many Issue Types (and even create new ones).
Which sometimes have nothing to do with Tasks or Incidents.
Therefore, it seems essential to me to be able to decide whether or not the Create/associate button is visible (or not) by Issue Type.
Imagine that I create a Custom Object "Car" in Salesforce, and an Issue type "Car" in Jira, with the brand of the car, the license plate, its color, etc. The creation button in Salesforce from Jira should not be visible in a Jira "Task" type issue because only the "Car" type issue contains the fields required for this record.
Jira makes it perfectly possible to manage fields and their display (or not) via Screens and Screen Schemes.
We should be able to configure the Create/Associate button (display or not, button location) with the Screens, by Issue Type