According to Worldbank https://www.worldbank.org/en/programs/icp/brief/VC_Uses and OECD https://www.oecd.org/en/data/insights/data-explainers/2024/0... this metric is a poor choice when trying to establish some sort of strict country ranking.
We live in a global world where no country is self sufficient. We depend on oil from a few countries, clothes from some other, electronics from some more, so on and so forth. In such an interdependent and connected world, all payments are made in global currencies and PPP in isolation doesn't really cut it.
India pays the same in $ for oil, as does let's say the UK. Similarly, when an Indian travels abroad, they pay the same in $/£/€ as let's say another globe-trotter from Europe.
PPP in such cases becomes a facade, to stoke their egos and to justify to the nationalists that their nation is doing well.
In very general term, you either use GPD to compare countries' "economic strenght", or GDP per capita (PPP) to compare how it translate for their potential for each citizen.
I feel like GDP per capita (non PPP) or GDP (PPP) are not very useful unless you want to make the numbers say whatever your story claims.
GDP comparisons in USD work really well when a large percentage of a country's economic activity is anchored to USD-denominated trade.
For some random heterogenous examples, if you want to look at Canada, China, or middle-eastern petrostates, comparing GDP in terms of the US dollar is probably your best metric, because their economies really are highly sensitive to changes in their currency's exchange rate to the USD, either due to the things they are reliant on buying from the USA (Canada), or the things they are totally reliant on selling to international markets (China, middle east petrostates)
On the other hand, for places like the European Economic Area, comparisons in terms of USD are quite a bit harder to justify, and this is where PPP can come in as (highly imperfect) alternative. The reason is that while they obviously are plugged into the global economy, they also do a much higher percentage of their economic activity in their own little economic bubble that's not as sensitive to their exchange rate to the USD. For example, European countries have had highly stagnant GDP in USD terms since 2008, and that does strongly affect things like multinational corporations, tech purchases, and energy prices, we're not really seeing any of the indicators on everyday life you'd expect from such a longterm stagnation, and that's because their economies really are growing, it's just that their currency is also losing ground against the USD even as they grow.
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TLDR: I'd compare Canada versus the USA in terms of USD, but I'd compare France versus the USA in terms of PPP. This decision really needs to be done on a per-comparison basis, and neither is really great, but for some comparisons one is much more appropriate than the other.
USD/EUR is pretty much where it was back in 2015 despite of the swings (in both directions) since then.
The Euro crashed in 2014 there was no real gradual decline which would explain this stagnation/growth.
even in inflation adjusted PPP, France was at around ~51k per capita back in $55. There is very little growth (of any kind) outside of Central/Eastern European EU countries and a small few pockets.