There are many reasons that people gamble.
Just look at this detailed article by Psychology Today entitled Why Do You Gamble?
We learn that gender roles play a contributing factor when determining preference of chance-based versus skill-based games.
Older people tend to choose activities that minimise the need for complex decision-making or concentration.
We may never know all the reasons why a single person decides to gamble!
BUT - there is one thing we can say for sure:
The majority of people (gamblers or not) know that Blackjack is a thing.