A canted footbed is angled slightly outward to match the natural alignment of your legs and knees when you're strapped in. Instead of your feet sitting flat, the inside edge is raised a few degrees, which takes pressure off your knees and helps you ride longer without that achy, worn-out feeling by the end of the day.
Canting is especially helpful if you run a wider stance, since splaying your legs further apart increases knee strain. But even riders with moderate stances often notice less fatigue and better edge control. If you've ever experienced knee pain while snowboarding, canted footbeds can make a real difference.
Most mid-to-high-end bindings now include built-in canting, typically between 2.5° and 5°. If your bindings don't have it, you can often add it with aftermarket footbeds. It's a small detail that has an outsized impact on comfort, especially on long days or deep carves.