To be very clear, there is no “import” function for PDF into InDesign. You “place” such content. Any annotations, links, embedded files, etc. as well as most metadata from within the PDF file is discarded as part of the “place” operation.
While there is a technical difference between the functions "place" and "import", the terms are used interchangeably. When I "place" a PDF into InDesign, I still can choose "import" options. When I "place" a word or excel document into InDesign, IMO I am technically importing. And although I can't "import" a PDF, I can "import" PDF comments into Indesign.