He's trying to get a retaliation from NATO, and then use that attack on Russia as a valid reason to call general mobilization. Without a good reason he can't call mobilization. And it'll boost his standing with the population with a good ol' rallying around the flag.

If NATO stays cool and gives a pile of cash to Ukraine in response for deploying drone air defense at NATO/Russia border and more support for Ukraine to attack Moskou it'll do the opposite is what Putin wants. If every stupid attack strengthens the enemy he'll attack less.