IG’s $1 Billion Bet on Tastytrade, page-5

I think SWF's revenue per active trader per year is about $300 AUD (brokerage from 1.9 trades per month, interest earned, and premium subscription).

I think Tastytrade gets more like $1000-1500 AUD per trader per year. From margin made on options, and maybe margin loans or similar.

So if SWF offered options or similar, which I think I have heard mention of, then there's some upside. But you'd still not expect every user to jump to huge revenue per user. More likely there would be ~10% take-up, so 10% of users would have the attributable revenue jump a lot. Though having to be careful not to damage the brand, about it being safe for ETF investors, who it's quite popular with.