For amateur players, sure. But there is an easily memorizable table by which to play BJ perfectly, either basic strategy or counting cards. So you always clearly know what you should do. If you are playing BJ to win, it stops being a test of rationality.

Whereas even when you become skilled at poker, it is still a constant test of rationality both because optimal strategy is complex (uncertainty about correct strategy means lots of opportunity to lie to yourself) and you want to play maximally anyway (uncertainty about whether opponent is making a mistake gives you even more chances to lie to yourself). Kinda like life...