An official port is certain to have no tampering, like viruses, trojans, miners, or spyware.
An official port does not make the compatibility of the game reliant on third-party software the author has no control over.
A proper port also adresses the issue of a PC-scaled interface on a phone screen, unlike Joiplay.
Then of course, convenience and capsulation. Installing an APK beats having to organize a bunch of game files and messing with an emulator.