PPP has meaning only in the context of multiple currencies
That's not true. One does not use a uniform conversion factor across the Eurozone.
The crude meaning of GDP converted at PPP rate is "how much stuff at local prices does this country produce/consume".
Why would you ever want this?
That's not true.
It is true. If your nominal GDP of, say, Germany is different from the PPP-based GDP then you're measuring the same GDP in two different units. One of them is the standard Euro, what is the other unit?
Why would you ever want this?
I don't understand the question. For example, I find it useful to know that China's GDP using the official rate is very different from the same GDP using the PPP rate. It gives me better understanding of the Chinese economy and its place in the world.
Previous Open Thread
You know the drill - If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one.
3. Open Threads should start on Monday, and end on Sunday.
4. Open Threads should be posted in Discussion, and not Main.