What does “deferred stock update” do and how is it related to Backorders?

Question

In M2 what does "deferred stock update" do and how is it related to Backorders?

From here it is not exactly clear what it does, especially what it has to do with Backorders (which is quite fast when compared to MSI). https://support.magento.com/hc/en-us/articles/360048996811-Magento-best-practices-for-deferred-stock-update-

Answer 1

when using MSI, there is no any reason to use "deferred stock updates". In fact deferred stock is a functionality which postponed real stock deduction for products with enabled backorders, while in case of MSI this deduction is postponed by default for all kind of products, as reservation mechanism is being used instead. Thus, MSI fully substitutes "deferred stock updates" and is recommended way since Magento 2.3

Answer 2

Use Deferred Stock Update is a feature of the enterprise edition of Magento.

Deferred stock updates are used for an individual product or an entire website all product and Take benefits of the job queue mechanism to allow inventory levels to update asynchronously after the orders are placed. Its Enterprise Version feature.

Reference: https://community.magento.com/t5/Magento-2-x-Admin-Configuration/Use-Deferred-Stock-Update/m-p/67676#M1454