Sure, that’s true. However, I would personally like to know whether “all my files being out in the open forever” is a thing I need to worry about in addition to all the default problems

If encryption gets cracked by quantum computing, everything digital that's connected to the Internet, is "out in the open" until quantum-proof encryption becomes the norm.

The only way to be sure would be to physically self-host with the option to air gap the storage from the Internet.