I think it has a point of putting more of the global oil reserves under Yuan control.TBH I'm not too fond of this kind of short term exploitation if it is true. I'd much prefer if China is able to establish some long term institutional change in Iran that is irreversible and firmly put Iran into China's camp and prevent them from flipflopping every few years.
In comparison buying some cheap gas just seems so short sighted.
China needs to start aggressive to eat up as much exclusive contracts as possible. It can tone down later, with the added benefit that it will be considered a goodwill gesture.
Iran might flip flop from going at it alone to going at it together with SCO, but they've never flip flopped from being against US since the Shah got deposed.
Like many others, I also think political change must come to Iran. But talking politics now would likely cause Iran to just go lone wolf.
However, if China can work through the brokers of power within the Iranian government, through business interests, investment and through education, then eventually, there will be real popular support for political reform.
Just having Iranian tourists be able to freely access China, exchange students, open up a world class consumer goods choices for Iranians, while at the same time slowly buying the loyalty of the pragmatic oil/business elite, that alone will have vast impact on Iran's politics, more than any demands China can make verbally right now.