Does Anti Aliasing really make games look better/ is it worth it?

Well, AA itself is not the important thing. To me, it's all about the textures and the shadows. High resolution textures makes anything just look marvelous, even Minecraft. Shadows add the realism to the game. AA does help smoothing out edges, as you said, so it aids in being more immersive, but it is not as crucial as the other points. If you're used to playing without it, then don't worry about it. Just focus on textures and shadows, and you'll definitely see an improvement. Save you some precious fps too.

It makes games look slightly better, but usually the frame rate hit outweighs the quality gain, especially with high quality textures and high screen resolution.

Depends on the type of AA used. The best/original method is supersampling but that causes a heavy performance loss. There are a lot of post processing techniques now that have a similar effect without the performance loss, though they do make edges slightly blurrier

Depends on the game, really. If I can get away with high AA and it not screw with the FPS, then I go for it, but removing a few jagged lines at the cost of frames that I really need... no thanks. I personally care more for model/texture quality anyway.

AA is by far the least important factor in gaming.
In my opinion, frame rate > graphic setting > anti-aliasing > ambient occlusion

Are you buying a prebuilt PC? Or is it a laptop?

Just asking since it seems kind of weird to have a mobile chip inside.

if this is a mediocre PC, i don't know a word to name mine. you made me upset sir. you are a bad person.

I like to call anti-aliasing "fake resolution" for it only tricks you into thinking there's more pixels in your screen by smudging hard edges like this.
IMO, if your pc is capable of running a game at your monitor's native resolution, there's no need to add any AA to it :)

It's important to me but I would never upgrade just to use AA. It is the first thing I disable if I need to improve my performance. These days FXAA/SMAA are implemented well in games so turning it on is a no-brainer to me. If I can choose FSAA/MSAA it is even better. Right now I'm playing diablo 3 with AA applied through nvidia inspector instead of the in game AA and the image quality is much better.

That said since you have been so used to low-medium settings it shouldn't matter .. just use any post processing technique and you'll be fine.

It up to you to decide what your own opinion is. Just because some settings are important to some people doesn't mean it should be important to you. But I might suggest that if it doesn't bother you now, never turn it on. Once you notice the difference with some graphics settings there's no going back. Then at some point in the future you get a new game where you need to disable some options for it to perform well, and the absence might bug you. Not so much with AA, but in my experience the best example is vsync. Somewhere around 15 years ago I noticed screen tearing for the first time. Now I hate playing with vsync off, and usually try to force it if that setting is not available in-game. Personally I notice the "stair stepping" on straight edges when AA is turned off and I prefer it to be enabled. But if it's never bothered you before I'm truly happy for you and hope you never begin to notice it.

If you get decent performance with AA on it's worth it if you can tell the difference.