In English, one possible use of the verb to do is in combination with the pronouns it/this/that to form a stand-in for a more explicit action when the action is already known to the audience, like so:
I'm doing this because it's necessary.
(Possible stand-in for the more explicit "I'm knocking this wall down because it's necessary.")
Why are you doing that?
(Possible stand-in for the more explicit "Why are you knocking that wall down?")
I saw him doing it the other day.
(Possible stand-in for the more explicit "I saw him inflating balloons the other day.")
Can faire ça/cela be used the same way, as a replacement for nearly any action in general?
Je fais cela parce que c'est nécessaire.
Pourquoi est-ce que tu fais ça ?
Je l'ai vu faire ça l'autre jour.
Is it natural even if someone specifies a different action? E.g.:
Pourquoi est-ce que tu tournes en rond en courant ? (Why are you running in circles?)
Je fais ça parce que j'attends mon ami et je suis impatient.