I just hope that this doesn't seriously backfire on NATO, as I strongly suspect that some NATO states are providing significant assistance behind the scenes to both Ukrainian forces and anti-Putin partisans within Russia. Much as the outcome from attacks like this may be beneficial for Ukraine, and to be welcomed, there is only so far one can go with poking the Russian bear within its own territory before it turns around and does something completely and absolutely irrational.
There is a pretty sound argument for not attacking Russia within it's own territory, notwithstanding the powerful emotional incentive to hit Russia hard for what they are doing to Ukraine. It's far too easy for Russia to use attacks against Russia, deep inside Russia itself, to motivate more Russians to fight in this war, via their propaganda machine.