Two models, side by side
Why parallel spends don't collide
An account balance is one slot two spenders can fight over. A UTXO coin isn't. Two demos below show what that difference does: first to a wallet, then to two apps trying to act together.
Try it: the collision
Who wins the same slot
Send two spenders after the same account balance, two different coins, or the same coin twice. Only the same-coin case hard-conflicts: the first spend wins outright and the second is rejected, not queued. The account case just lets both writes land, one after the other. The full demo also lets you spend, combine, and split the wallet itself.
Try it: race for one slot
Race for the exact same data
Narrow the same question to one specific value two writers both want right now. Run the race on Kaspa's UTXO model, then switch to an account model and watch both writers land instead of one getting rejected. The full demo goes further: two separately built apps composing inside a single transaction.
Go deeper
Read the sources
Both demos above link to their full versions, with the reasons and sources behind every claim, and how GHOSTDAG orders a real collision.