On the bright side, using these weapon grade malware is burning exploits and also showing current state and techniques of Russian cyberwarfare which defender can learn a lot from.
Or perhaps they used an already-known malware to measure defensive capabilities without showing any of their cards.
This is vastly different to real world military systems, where there are a lot more variables and no guarantees - i.e. countries have limited numbers of air defense systems and missiles, the missiles have finite non-zero flight times, the physics of detection systems and sensors are not absolute etc.
The real world is just more complicated, so the value of buzzing someone's airspace reveals a lot more information then "huh, guess they didn't click on that email".
Not that it matter anyway at all... since there aren't any major rivers separating Poland and Ukraine to begin with.