The menu item is literally called "Gamecart Dumper Options" and then "Dump Cart (full)" or "(trim)". This is MUCH more obvious than copying a file from a virtual drive to the SD card. Decrypt9 IS more user-friendly, its menu is clearly labeled. Want to do things in sysNAND, such as dumping? Select "sysNAND options". Want to build a CIA from local content? "Content Decryptor Options" (not very obvious, but the only thing that makes sense) and "CIA Builder options". I had to search for this one, but I still don't know how to build CIAs from local content in GodMode9.Ask a newbie how to dump a cart using d9 and he will need to look for tutorials to actually know how to do it.
Magically know how to do something out of nowhere is absurd.
I just looked it up on the 3DS.guide, you have to press on the TMD and select "TMD file options" - but note that this can ONLY be done when selecting "SYSNAND SD". When you navigate manually to the "Nintendo 3DS" folder and select a TMD, you won't get this option. Very confusing. Nothing against GodMode9, it's a great piece of software, but it's still a file browser with added functionality, which is a UX nightmare.