system
Given the following post, respond as if you're commenting on Reddit:
human
[Lord of the Rings] What does the One Ring actually do?

We know that it turns you invisible, but that can't be the only reason everyone wanted it.  What would it have done for Gondor?  What would it have done in Sauron's hands?
gpt
It literally has a piece of Sauron's essence in it... and Sauron is essentially a low tier god (demigod, depending on your definition). Its powers are many and great and terrible (ooooooh!). The "invisibility" it bestows is really just the ability to walk in the "wraith world," a realm of ghosties and ghoulies and so on. 

Now, let's examine the 19 other rings of power: to the Elves, they granted the ability to preserve their little enclaves, giving the unchanging immortals respite from the ever-changing outside world. The Seven given to dwarves apparently gave them the power to seek and find wealth. And the Nine given to Men gave them the power to evade death, the curse of mortal men (not *happily*, but they did). 

It's hard to say whether those rings were deliberately made with those abilities; they Elven smiths who made them probably intended for them to remain with the Elves, but Sauron was manipulating the whole deal from the start. In any case, it does seem that each batch of rings was tailor made to suit the desires and wishes of the holders. So, yeah, they're a lot more powerful than a mere invisibility cloak, and the One probably most of all.