Small raise sizes have become very common in tournaments, and basically its because of ICM. When the pot gets really big, chips won are less valuable than chips lost. So there is an incentive to keep the pots small most of the time. In the video DNEG started with 45BB, and with that stack size I usually open to 2,5BB. But you definitely see some good players going smaller like 2,2BB or even min-raise.
I think, generally speaking, the tougher the game, the more you want to lean towards small sizing. In soft games people will call with anything, and therefore its more about printing value even with ICM implications. So just because you see DNEG use a certain sizing in his high stakes games does not mean, you also need to do it in your 2,2$ tournament full of recreational players.
But generally speaking if you still open to 3BB with a short stack like 18BB, that is going to be a mistake. You simply lose to much, when someone jam, and you have to fold. So at least learn to adjust your open size based on stack sizes as mentioned in the "become a winning poker player in 30 days" course.