The principle of hedging is that two assets hedge each other if their price demonstrably evolve in opposite directions. For instance, if a bank sells an equal amount of puts (the right to sell at a given time) and calls (the right to buy at a given time) on an action with the same strike price and the same maturity, it is hedged: both positions cancel each other.

Since BTC has no underlying asset, it's hard to demonstrate a correlation with anything. So if you buy btc as a hedge, you could pretend you're hedging against anything. In reality, the only significant factor is btc's popularity.

That means you could probably buy anything that isn't correlated with Euro and get the same result.