Yeah the tipping toes bothered me a little bit too at the beginning, but eventually I came around with these thoughts:
First, those were probably done to simulate the effect of wearing high heels, which adds to the elegance of the figure, but of course an ancient Goddess can't be wearing high heels, so what's the next closest thing? Tipping toes!
Second, Hera is a Goddess, I won't be surprised that she possesses some kind of anti-gravity capability (e.g. walk in the cloud), so maybe that's actually how she really walks! No worry on losing balance or hurting toes.
My $0.02