There are reasons why it is considered as strategy. In gambling the results are based on probability and if we take the dice 1/6 is out winning chance of the bet and we can't say that if we bet 6 times we will atleast win once since the results are respective to each bet but in general more we play and more we stretch the chance of winning is there and with another example if someone bet $1000 on a single bet of any game and going all in their might win and make it big or lose everything and get home with nothing but if someone decided to go with $1 of 1000 bets then it has serious chance of winning and more or less we will end up with more than $1000, so it is a strategy.