Hi,
Unless you have your characteristics selection method set to list, there is no listing of variants on the frontend, and thus no listing of variants to be filtered.
Also, when you have a list of variants on a product page, you usually only have a dozen of variants, sorted based on the characteristics. A filter wouldn't be much needed there.
So I'm not sure what you're saying ?
Or are you saying that you would like HikaShop to be able to have listings of variants, not only listings of categories and products on the frontend ?