The lesson says:
When using "faire de la danse" or "faire de la natation" (FOR EXAMPLE) rather than simply "danser" or "nager", you refer more to an organised, repeated activity - I take dance lessons / I go swimming [as a regular activity, e.g. attending class or lessons] - than just a 'one-off' activity you're in the middle of doing such as I'm dancing / I'm swimming.
How would one then say: "I am dancing / I dance" without implying one is taking dance lessons? Same for swimming.
Thanks.