How does Freetrade make money?

Yeah I was surprised they stopped charging for instant orders (I would have been ready to pay for that!).
I think they were right to keep charging the 0.45% FX fee to become profitable.
Yet I dont get how they expect a revenue of £20/customer in 2020 and £70 in 2023 (revenues from Alpha only accounts for 25% of the forecasted £242m-revenues)