Yes, non-passive effects are much easier to understand. Everyone can just look into the timing structure of an Action, and immediately knows when to resolve Disrupts, Responses etc… With passives, this is sometimes very difficult.
The Pillar's effect could be worded as an Action easily (likewise to Dirk Sharpe, e.g.). The difference is, Actions can be cancelled, but passives cannot. I guess that's one reason for the Pillar to be written as it is. There is another passive that is similar, although I had to dig a little for it: Sweet Old Lady (Opponents must pay 2 in order to commit characters to a story where Sweet Old Lady is committed alone.) Her passive also follows the "pay a cost to commit to story" pattern. But I guess that information isn't very useful ;-)
If you want to know how it works… In contrast to e.g. Dirk Sharpe (which is commited not with all other characters of you, but either before or after), Guardian Pillar is committed concurrently with all other characters of you. That's another reason for his text being a passive - usually, supports can't commit to stories, but this passive "bends" the rules so that this card can also commit to the story alongside other regular characters.