On your settings page you can select what languages you want to see and block everything else.
But most people leave post language unspecified, so you have to include unspecified in your list of accepted languages. That makes the language filtering somewhat useless.
When you select some languages on the settings page. The language selection on the post editor will be restricted to that short list of languages, which makes selecting the language easier.
Yeah, if you have a smart tv, you’re being spied on.