However i'm still curious to know if it is just a usuall UBS driver with software inside or if this stick hide special hardware.
Nobody can know without spending their money and reviewing it. But i wouldn't recommend anyone to do it, since it's likely to be regular USB storage with certain live linux/windows and several cryptocurrency apps.
What is the benefit of using TailsOS vs Live Ubuntu, i guess the nodes don't get my IP so
it is better for privacy, but does it improve security?
Tails OS also take security seriously. It also have built-in Electrum (although usually it's somewhat outdated) and provide encrypted persistent storage, which make thing more convenient.