SteveC
Doing the best imitation of myself
It's a simple answer: you use it, and other skills, all the time for all sorts of reasons.@Undrave and @SteveC: If that's the case, why is not used on other spells. You are giving me very elaborated answers but not addressing the point. You don't have to explain me what Arcana does, you have to justify why is used here and here only.
I wasn't aware of the Conversational method of running a game, but I was doing that even back in those days. We play in a conversation. I tell you the situation, you ask me questions about it, and then eventually tell me what you're doing.
I check if you have a power or ritual that either lets you do this automatically or has special rules for it. If not, and I believe you should be able to attempt it in terms of the Fiction, you make a check (if there's a chance of failure and consequences for failure). We see if it's a success or failure, and then I narrate how the situation has changed. And then we go back to you telling me what you're doing now.
Think of it as an informal skill challenge where there's a situation, and you tell me what you're doing to address it. I've been running games that way since the 90s, and I think 4E's skill challenge rules encouraged me to do it that way. It's how I run 5E or Pathfinder 2 now. And how I run Fabula Ultima or Daggerheart.
I think a lot of this comes from how we used to play 0E back in the 70s when you didn't have powers at all and you had to do everything this way. DM describes, player tells, and then you roll a die if you need to figure out what happens.