What are the advantages of current transmission over voltage transmission?

 

That is not a reasonable question. It requires a difference in potential (voltage) to cause a flow of current). You can't have one without the other.

It is usual to have very high voltages in power transmission to minimize current. Look up the price of copper to see why.

 

Perhaps the OP is referring to the transfer of information via current rather than voltage?

In a series circuit, there will be voltage drops along the way, but current will have the same value at any point in the circuit.

 

Hard to tell with only the one line given.