Standard tinned finish can be a bit uneven. Not an issue for lots of components, but can cause problems for some more specialist packages
Gold plated finish option is really good when dealing with BGA, LGA, etc packages, where you really want a perfectly flat high quality finish to ensure the BGA package will sit perfectly flat and solder without any potential rough surface issues.
Note that gold plating of copper is not the same as gold fingers for edge connectors. Standard PCB gold plating is soft, if you need gold plating of contacts for insertion and removal into connectors then you need a tougher gold finish on these pads.
Black soldermask is typically gloss black which is horrible don’t use it (mat black is nice)