The two pieces noted feed devices with high-impedance inputs (say 50,000 or 100,000 ohms) that require virtually no current. The voltage reading dictates the operating parameters.
Contrast that to a low impedance device such as a 4 or 8 ohm speaker where the resistance is so low that current draw is significant.
Contrast that to a low impedance device such as a 4 or 8 ohm speaker where the resistance is so low that current draw is significant.