I don’t understand how .fig files are saved. I need to save them to my computer so they can be archived on external drives (for client work as part the contract - so having them only on the cloud/Figma is not an option). Why doesn’t this work like other files? And why when I try to open the .fig document on my computer does it not open the file.
To open the .fig file you need to import it into Figma.
.fig files are not a reliable backup solution, keeping the files stored in Figma is.
Figma is purely an online tool so there is no way to open the file offline or without Figma somehow. But you can use other tools like Sketch, I believe it now has Figma import feature.