Zelensky loves offensives. He has quite a bit to show off (~1000 sq. kilometers) for modest Ukrainian casualties.
The Russian army might have a few more forcibly retired generals soon. One or two might actually be competent.
On the other hand, Putin might gain support for his costly and probably somewhat unpopular war.
The Russia operation in Kursk is being run by Putin’s ex-bodyguard and the FSB. Not the Ministry of Defense.