[McGruff]

Why would Russia waste an expensive missile on an apartment building. More likely one of the Ukrainian S-300s either shot down the Russian missile or just missed and came back down to earth there. And it was just a small part of the building looking at the picture.

[buwaya]

A very good question.
But the location of the targets, whether the missiles were intercepted or not, shows a major shift in target priorities.
Electric infrastructure tends to be far from civilian areas.

One possibility is that these missiles were intended for bridges and highways, in built up areas (to create rubble) in order to hinder Ukrainian force deployments. A miss would be likely to hit civilians.

[Timber Rattler]

Why would Russia waste an expensive missile on an apartment building.

To terrorize and kill Ukrainian women and children and the elderly.