Looking at the upper right black circle, if the Russians can push through this area they can link up with their forces east of the Dnieper in North Eastern Ukraine, cutting off the Ukrainian forces currently preventing Russian advance across the river in Eastern Ukraine. The Russian forces in the Kherson region are supplied through the Crimea. First over a Bridge crossing over the Black Sea from Southern Russia, then over these 3 crossing points below Kherson. There are a large number of Russian forces in the Kherson region above the Dnieper hoping to break through the Ukrainian defenses so they can cut off the Ukrainian forces to the North.
However, if Ukraine can capture the 3 logistical bottle-necks south of Kherson all of the Russian forces above the Dnieper will be in serious jeopardy of being slaughtered due to lack of supplies and the inability to withdraw back across the Dnieper. As a result the Russians have moved many of their forces into the Kherson region to prevent the loss of Kherson. Recently the Ukrainians destroyed the 2 bridges which cross the Dnieper leaving the Russians with only the Dam as a logistical crossing point.
One might expect the Ukrainians to blow the dam. First, it is against the Geneva convention to destroy such structures. It would result in untold immediate and prolonged damage. The entire Crimea, (Russian controlled Ukrainian territory) would be without power. Massive flooding and international condemnation. Death from exposure in the Winter. It would also require heavy weaponry the Ukrainians have yet to receive.