How is Wishlist Bundles different than using Wishlist’s Sequential Upgrade feature?

Although there is an option to use the Sequential Upgrade feature for creating bundles, however it is not the best solution and it makes the bundles option impossible in complex scenarios, for example: If you want to sell level 1 + level 2 + level 3 in different combinations and bundles, but you also want to sell each level individually. Also, using the Sequential Upgrade for multiple bundles can be very confusing an is presented in a non-visual way in the Sequential Upgrade settings, which can cause confusions and lead to creating wrong bundles.