No better penetrator has been developed (hardness, target killing ability, cost of manufacture), so it will continue in use.

Some degree of biohazard from continued decay of the uranium is possible, and it seems likely that some degree of contamination from spent rounds occurs. People will accept this as the cost of doing business until the contamination cost exceeds the value of the munition.

Cannon and machine gun fire is not, after all, intended to create easy clean up -- its a tool for killing people and breaking things.