Regarding the full price steam purchases, I think Phillip has two reasons for this.
One: it means he has another tool to beg with: “Now guyz, I just spent (looks at camera to make sure he holds up the correct fingers) FIFTY DAHLLERZ on this game and I have twelve dahllerz in support.”
Two: He’s fucking stupid and impulsive. The schedule and Phil want to play the game, so he picks the easiest route to purchase the game, on steam. Could he use a reseller key site? Sure.
But that’s ADDITIONAL CLICKS YOU DUNCE AND IM A BUSY STREAMER.