Two imperfect metaphors that describe what happened in two levels of detail:

1. You ever gone to an office to talk with a super expert about something, but they are too busy. But, it turns out that their assistant was helpful and solved your problems without you having to wait around.

2. Whenever you want to work on Steem, you go down to the steem office. There's this one really smart giant, but kinda grumpy robot who takes your request and goes to work magic on the blockchain then gets back to you. They tried making his brain bigger and giving Botty tons of coffee to get him to work faster. They even tried giving him more arms. Still Botty got way too busy and developed a bit of a temper. It's pretty hard to build more like Botty because he's fat, has a ton of custom parts and fills up the building. He also slurps down the electricity and takes ages to wake up if he goes to sleep.
   But, it turns out that most of what botty does is read stuff from steem. And, there's some bots made from high quality mass produced parts that are way less fat, slurp less power and wake up super quick when summoned. These bots are super good at handling your steem requests and remembering what they read just in case you or the next customer needs it. They don't like to bother Botty unless they need too. These guys are called Jussi.
   So now, you when you go to steem office you talk with any of the available Jussi bots. If you're just asking to read something, chances are your Jussi bot can pull it from their memory. When Jussi can't remember something or they need to write something into the blockchain (like upvotes, postings etc) then they go ask Botty and get back to you at super fast bot speeds.
   When the steem office gets really busy, it's super easy to open up more counters and have more Jussi bots ready to serve - afterall Jussi bots are made from cheap mass produced but high quality parts. When steem gets less busy then some Jussi counters can be closed to save power.

That's kinda what happened.