Precisely. So what did Cameron want in the reforms?
"An explicit recognition that the euro is not the only currency of the European Union, to ensure countries outside the eurozone are not materially disadvantaged. He also wanted safeguards that steps to further financial union cannot be imposed on non-eurozone members and the UK will not have to contribute to eurozone bailouts."
"Measures, the purpose of which is to further deepen the economic and monetary union, will be voluntary for member states whose currency is not the euro.
"Mutual respect between member states participating or not in the operation of the euro area will be ensured.
"Legal acts... [between eurozone countries] shall respect the internal market."
"But Mr Cameron ran into unexpectedly firm resistance from France on financial regulation. The French wanted to underline was that Britain would not win any "exceptions to the rules of the EU" - particularly in relation to regulation in the City - hence the addition of the "level playing field" line. Mr Cameron got his explicit recognition that the EU has more than one currency - but it does not go as far mandating "multiple currencies".
Now what about any of that says "immigration" to you?