The later game fights were just really chaotic and I don't really know what was going on in any of them.

I knew this but I haven't internalized it. Important!Nope, it heals you for every second of hearth cast time in bulk when you appear in the hall of storms. I have checked it frame by frame and you heal faster by hearthing in every single situation, unless you are only 1 frame away from the hall of storms, in which you heal at the same rate.