For the casual section I think one solid paragraph is the requirement. I don't think you can make one of those, and an interesting one at that, if all you do in one turn is set a card down on the field. You're right that space isn't an issue, but if it's just space taken up by three sentences detailing activating some cards in response, it's just clutter to me.
Even if people get to react to the ongoing duel, what are they going to say? "Oh no spirit partner! That guy is really tough! I sure hope the other guy can find a way out, and that we can last against whoever wins! Looks like we have a lot of work to do!"