VCs sometimes follow "hot" companies. Companies become hot when several VCs think they are hot for whatever reason. When the company is hot and gets offers, other VCs will rush to give them more offers and at that point you might not even need a deck or any metrics anymore. The startup can then bid those offers against each and can end up raising even more they initially were trying to.

Fast did great job hyping the company on Twitter, likely the founder also was a good storyteller. The old adage is that you raise with a story, team or traction. Sometimes the story actually pans out, like with YC Airbnb is often an example of company that struggled for a long time in the beginning and no-one could really predict how big they could become.