Euro, is very spendable, mostly stable.
Then you've never watched it's 25%+ fluctuations up and down over the last 10 years.
You can't measure the stability of a currency just by comparing it to your own currency. If we followed that line of reasoning, the only stable currency to you would be one which is pegged to the US Dollar. The price of one Euro fluctuates if you measure it in Dollars, yes, but that does not speak against the stability of the Euro more than it does against the stability of the Dollar.