Money, specifically $20k per app per platform (assuming you're not a small startup). That's Avalonia XPF, though, not the open source component; XPF is an alter

Money, specifically $20k per app per platform (assuming you're not a small startup). That's Avalonia XPF, though, not the open source component; XPF is an alternative platform to target that'll turn WPF into Avalonia without rewriting any code. If you're willing to rewrite/port code, you can use the open source stuff and get the benefits for free, of course!