The method isActive() should be removed from the interface \Magento\Payment\Model\MethodInterface, because it is used only by a particular interface's implementation \Magento\Payment\Model\Method\AbstractMethod and by vault payment methods

dmitrii_fediuk (Dmitrii Fediuk) February 9, 2016, 4:14am 2

See also:

The method canOrder() should be removed from the interface \Magento\Payment\Model\MethodInterface, because it is not used outside of a particular interface’s implementation \Magento\Payment\Model\Method\AbstractMethod
The method canAuthorize() should be removed from the interface ``\Magento\Payment\Model\MethodInterface, because it is used only by a particular interface’s implementation \Magento\Payment\Model\Method\AbstractMethod and by vault payment methods