That's actually the one I'm entirely on board with

Many retro games were designed to be viewed on a composite (or worse) signal CRT (particularly 8/16-bit consoles). They take advantage of the characteristics of those technologies to act as a final expected phase of image "processing". (It's a physical effect so not actually processing)

The games were never meant to be played with sharp, hard pixels. The lines were supposed to blur a bit to create a sum greater than the parts and create additional chroma and luma resolution that isn't possible with the console hardware in isolation.

OTOH it actually has to be a good filter that mimics these characteristics correctly, if it's just basic 1px scanlines and nothing else I'm probably not gonna use it

Just put the grease on your own eyeballs and sit really close.

I've heard it explained with the joystick controlling the head of the character.

Imagine a joystick sticking out of the back of their head. That's your controller joystick.

Depth of Field is the blurring effect to draw focus onto an object. Like when you ADS and everything except the area around the gun in your hand becomes blurred. The assets are already visible and loaded, and the effect is a shader.

You might be thinking LOD distance or FOV.

It makes everything blurry

I'm on a CRT screen for reducing delay, too, so yeah. I render at least 2x fps than my screen refresh rate so I never visually perceive any tearing anyway.

It's not tiny, you just don't know the difference if you're used to a flat panel display. If I play on a friends' PC I am constantly aware of the difference, but it is definitely something your brain eventually just adjusts to and you stop perceiving the lag.

In my experience it causes a very large amount of delay in almost every game I have used it on. Even in a casual gaming setting it can make playing feel a lot worse.

Same but there is more than one way to solve screen tearing. If you can render frames at at least 2x the screen refresh rate, it will never visibly tear.

Nothing’s moving on the screen. You’re reconstructing movement from a series of still images.

Motion blur—when it’s implemented with understanding of why it works—provides additional information about speed and direction of movement in a way that your brain is naturally apt to deal with.

Without motion blur, you need at least two frames to figure out direction of movement. With it, you’ll have enough information to start priming response in one frame. And consistent pattern of priming actions and successfully executing them translates into a physically satisfying experience.

I also dislike motion blur and turn it off because it gives me a headache, but let's not pretend that motion blur doesn't do anything at all, because it does.

Motion blur happens in real life when an object moves quickly through our field of view and the image smears on our retina. But the effect is different depending on speed and distance; a car whizzing right past you appears blurred, but watching that same car at the same speed when you are standing 200 meters away is not blurred, because the car occupies less of your field of view and so moves relatively slower across it - slow enough to not blur.

To get one thing out of the way, old LCD monitors especially (but even some newer monitors) can intrinsically suffer from what looks like motion blur, which is when the monitor can't update quick enough and moving objects leave a kind of ghosting or smearing effect behind them. High quality screens however will have very little noticeable intrinsic blurring.

Assuming a decent screen then, motion doesn't intrinsically blur - not always. Sufficiently quick events will indeed still look blurred due to natural human eyeball motion blur, but lots of things that would blur in real life might not. The car whizzing right past you won't necessarily appear blurred at all, because what in the game represents to your player character a very close and fast movement is on screen perhaps relatively much slower and further away from the perspective of the human sat at the desk looking at it on a monitor, and so doesn't read as blurred to our eyes in the same way.

So, motion blur in games is an attempt to take movements that would look blurry in real life, and apply artificial blur to make them blurry on the screen.

I don't personally like in-game motion blur, and even if it didn't give me a headache I'd still turn it off for stylistic preference reasons, but it is a real thing, and does try to achieve something specific.

Maybe if you're trying to capture still images from a video stream?