Technical problems aside, there were probably many American citizens onboard. Landing in Russia. perhaps even getting a stamp in the passport, may not be very favourable for some of them.
I don't know what is the situation today but there was a time where American citizens visiting Cuba were very careful not to get a Cuban passport stamp. It was problematic if the US border police discovered such a stamp. So the Cuban authorities helped out by supplying a stamped card to said American tourists.
