A friend once left a comment asking about this, so let me explain it in plain English.
Cardano uses the extended UTXO (eUTXO) model, which builds on UTXO by adding the ability to execute script logic.
The account model is more like a regular bank account: the balance is easy to understand, and writing smart contracts is more intuitive. The trade-off is that transactions from the same account have to be queued and processed in nonce order.
$BTC uses the UTXO model. The balance shown in the wallet is actually the sum of multiple unspent outputs. The current price is 82112.01.
Had you heard about this before?