As I understand the lesson, faire du/de la is used for habitual activities and joue à is used for ongoing or current activities. Is this wrong?
If not, how come "Elle joue à la natation." is wrong for "She goes swimming"?
The lesson has "Tu fais de la natation" as an example where it means the person does this habitually/in a club or something. So wouldn't "Elle fait de la natation" mean "She swims", "She's in a swimming club" or something, i.e. that she swims habitually?