Actually, every economist in the world uses PPP for international comparisons. By definition, the whole idea of PPP is to facilitate international comparisons. I work as an economist in an international organisation and you would be laughed out of the room if you insisted that nominal GDP was a better measure for international comparison. PPP denominates all output in a common commodity basket, thereby making any comparison meaningful.
Surely you don't think a country going through a hyperinflation which causes nominal GDP to double has twice as good an economy as it did before?
Favouring nominal GDP on this forum has more to do with the preoccupation with each nations 'power' and strategic reach than the economic relevance of nominal GDP. The use of nominal GDP for comparisons of how powerful each nation is does make some sense. As a measure of economic progress, nominal GDP is nearly useless.
There is a deep theory of how appropriate PPP is as a measure. If international markets were perfectly integrated we wouldn't need PPP comparisons. As a thought experiment, think of the country undergoing hyperinflation I mentioned before. In a perfectly integrated world, the 100% hyperinflation would be matched immediately by a 100% currency depreciation and the hyperinflation would have no impact on dollar denominated nominal GDP. However in the real world, there is a lag and currencies take time to adjust to inflation differentials between countries. Therefore, using nominal GDP, the country undergoing hyperinflation also appears to be going through a dollar denominated nominal GDP boom, which is misleading. This necessitates PPP comparisons. I hope this helps.