You can see this poem on a background here - https://www.bitcoinpoems.pro/delivery094WhoControlsTheLedger.html

Money is just a ledger - a simple way to track who has what.  You can do this through commodity money, or a written or digital ledger.

Imagine you are playing cards with seven friends, and you each use pennies, or quarters, or poker chips, or jelly beans to track who wins and who loses.  This is an example of commodity money, where you literally give Lance 10 chips and you don't have them anymore.

OR, you can get a blank sheet of paper, and write eight names across the top, and keep track on paper.  You can each start out with 500.  Then when Lance owes you 25, you just subtract 25 from his total and add it to yours.  

Both commodity money and ledger money are simply ways to track who owns what and who owes what.  Over history, commodity money tends to develop among groups or nations who don't trust each other, and ledger money tends to work better in groups that mostly trust each other.

And, of course these days most ledger money is digital, for example, Venmo, PayPal, your bank account, and many more.  

But these require a middle man, or a company, and can you trust them?  Sometimes you can, and sometimes you can't.  

Can you trust them to accurately maintain the ledger, AND not create new units of the currency for themselves (which debases the value of your holdings)?  With Bitcoin, nobody is in control (and everybody is in control) - or more aptly, the code (or the rules) are in control.