I understand that remarks tag is used to provide additional information about the class but it is not displayed in intellisense while hovering / calling that class. I would like to know Where exactly it is useful?
Remarks are used for building a documentation file. They are used for more detailed comments, adding supplemental information to the "summary" tag ("summary" tag does show in intellisense).
The generated documentation file will be in XML format.
To generate the documentation file you need to add the "/doc" compiler option. In visual studio you can enable the generation of XML documentation file by: