You can use it for a ton of things, most leather that is used for jackets, personal items like purses and wallets (not all but alot), things of that nature. There are actually too many things to list really. So yes anything against your skin will be fine. For frogs I would personally use a strap type of leather, now strap leather can be tanned many ways one of which is chrome tanned so it depends on the leather. Thickness and type.
You can use it for outer lays or for a kind of inlay depending on how the leather looks for a contrasting look.