Key difference
This keeps the same alternating dumbbell curl pattern but changes body position to an incline bench, which lengthens the biceps at the shoulder and usually increases the curl path. Shoulder position can affect regional biceps loading and strength adaptations in elbow-flexion training. [1]
When to choose it
Choose this when you want the closest overall substitute with more strict form and less body sway than standing. It fits well if you have an adjustable bench and want to keep side-to-side control while increasing the challenge slightly.