There are many whales who might be wagering big amounts but not all of them turned out to be lucky and in the above case he has wagered on many matches and combined odds gave him such a big win but he must be having knowledge for them as well.Being lucky was another big contribution to his win and without it he would have lost that amount also.
A parlay composed of price spread type of bets only show how calculated his bet is. Maybe he is lucky by I would say that he gives a thorough analysis on his bet in able to come up with that kind of parlay build.
If he is just betting randomly, He will choose match winner because it’s easy to pick bets using a 2 choices only compared to price spread that has a lot of option depending on how much knowledge he got to the team that he is betting with.