What do they have in common?

Apparently, buying and selling indulgences.

A piece in Slate, How To Spot a Persian Prostitute: Streetwalkers in chadors, by Juliet Lapidos, informs us:

The penalties for prostitution [in Iran] are severe—ranging from whipping to execution. But there’s a loophole in Islamic law called sigheh, or temporary marriage. According to Shiite interpretation, a man and a woman may enter an impermanent partnership with a preset expiration date. There’s no legally required minimum duration (a day, a week, anything goes) and no need for official witnesses—unless the woman is a virgin, in which case she needs the consent of her legal guardian. An Iranian who’s wary of arrest can simply escort a prostitute to a registry, obtain a temporary contract from a Muslim cleric, and then legally satisfy his sexual needs.

QED (quite easily done).

Is this reminiscent of purchasing carbon credits for that jet flight to Bali, or what?

Were getting real meaningful emission reductions as simple.