'PF' was also pretty big in Asia's largest music markets. It sold over 1m copies in South Korea and is platinum in Japan. This means 'PF' was global, unlike 'Firework' which didn't sell that well in Asia.
So you agree that Poker Face sold 2M more but that it isn't a bigger hit? What even
It made more impact and it's more remembered. It's 2015, suddenly streams do not count? Do you want to take a look at the statistics on VEVO, Spotify etc?