Why can I not use existing CDT at "Generate New Action" in Record Type ?

There is a "Generate A Record Action" function in Record Type.

When Generating New Action some objects are newly created.

And for Data Store, Group and Folder, it's able to replace to existing object.

But, other objectcs are all newly made and cannot be replaced to existing objects.

Why can I not use existing CDT at "Generate New Action" in Record Type ?

Also I want the interface to go into interface folder, and rule to go in to rule folder which I already have created.

Hope these functions get added in the next update.

Thank you.