in sports kumite a takedown only scores points if it is finished with a punch. Here are some nice examples:
Now, I've seen several examples of similar finishing punches after a takedown in videos on practical bunkai (on this forum and elsewhere).
I would like to know how you feel about this? - From a self-defence perspective, is it a good idea to finish a takedown with a punch to the head or chest onto the downed enemy? - Or is it simply a habit from sports kumite that found its way into practical karate?
I expect the answer to be "it depends" and "it has its place". :-)
Personally, if I don't get pulled down by the other guy, I would rather not sink down to punch, because of the danger of getting kicked in the head or being grabbed. Instead I would instantly run, or first kneel into the enemy, dropping my full body weight into their ribs and/or head, and then run.
All the best