The list of ways we can be spied upon seems nearly endless, but you can add one more to that list: active screen snooping via your vulnerable monitor. And that’s just one flavor of attack that can be pulled off by exploiting monitors.
You might not agree with everything you read online, but you can usually trust that what you are reading was actually published somewhere by someone. Whether or not you like what the balance is in your banking account, most folks would not expect that number to be faked. The same would be true for a person monitoring critical infrastructure, but the information being displayed on a computer monitor can be manipulated and may not be the truth.