Well, we use the computer to bypass geographical limitations but there are many ways to accomplish the task. We usually don't bother with the computer at all, it is just easier to watch Netflix and Amazon Prime.
You can check the current listing on Netflix Argentina here: https://www.ennetflix.com.ar/
Maybe if you mention some of the content you are interested into, I can check it for you.
We have an Apple TV and we bought it from an American guy, so it definitely works here. On the device itself it states it works with 110-240 V and 50-60 Hz, so you are safe.
However, an Apple TV is just a device that makes your TV smart, i.e. it allows you to access Netflix, Amazon Prime, YouTube, etc through the internet. More modern TV are already smart by themselves, i.e. they can connect to the internet to access these services without needing an Apple TV. (Competitors to Apple TV are Amazon Fire stick and Google Chrome Cast.)
Video streaming services are subject to your current location due to commercial agreements. For example, in Argentina there is no Hulu, so that service is not available through my Apple TV. If I were to take the device in the US, it would take Hulu.
Last but not least, the programming available on available services is also geographically-dependent. I.e. when I access Netflix I get access to the Argentina Netflix catalogue, which is far narrower than the US Netflix catalogue. For example, on US Netflix the latest season of Grey's Anatomy is already available, but on Argentina Netflix it will become available in November.
That said, I watch mostly movies and TV series in English, if that's your concern.
