In Australia, they call thongs what the rest of the world call flip flops. This product is from Australia.
These Archie Thongs are proving to be very popular with Podiatrists in Australia and they can make a useful adjunct to foot orthotics and in some cases be used instead of foot orthotic therapy. The amount of arch support in these flip flops or thongs is the same as you would probably get from an over-the-counter foot support, so they can be useful for that.
In Australia, they are being stocked and selling well in Podiatry clinics with many podiatrists using them for themselves and family. A lot of comments often get made about these to the affect of you just have to try them on and them you will buy them.
They are going to be particularity useful to those who need foot supports or orthotics and for whatever reason they do not have footwear in which to wear them in. This is probably why they are so popular in Australia, its a lifestyle thing.