Let's try with another gif:
Does that help?
I do use the heel curve capabilities of an X28 when I use one.
What I appreciate about a heel curve or a heel and toe curve is the ability to saucer the puck without involving my wrists. The open face is made to elevate the puck as it travels from heel to toe. As always with the X28, the release point for this is earlier than it normally would be, otherwise the puck gets released in the rockered toe section of the blade. The problem then is, instead of the puck tilting upwards for liftoff, it partially loses contact with the blade, so the puck only lifts up on one side and falls on the other: flutter launch. If you release before the toe rocker kicks in, the heel works as any lofted heel curve does.