Common gate with low input impedance
The textbook says the common gate has advantages over the common source for the frequency response -- not the voltage gain -- so it is correct. It's not comparing the common source to the common gate for voltage signal applications specifically. Each circuit has its own advantages and disadvantages -- the common source has a better input impedance for a voltage input, but the common gate has better frequency response.

Despite its lower input impedance, the common gate is nonetheless useful in applications which use voltage signals. For example, the MOSFET cascode is a common source followed by a common gate which has an overall voltage gain comparable to the common source but much higher bandwidth.

A common source amplifier by itself works by converting the input voltage into a current (the drain current) using the MOSFET's transconductance \$g_{\text{m}}\$. The load resistor \$R_{\text{L}}\$ then converts the current back into a voltage which is taken as the output. Hence the voltage gain is approximately \$-g_{\text{m}}R_{\text{L}}\$. Unfortunately, the high voltage gain from gate to drain results in a significant Miller effect that reduces the bandwidth considerably.

The cascode reduces the Miller effect by connecting a common gate amplifier between the common source MOSFET's drain and the load resistor. The overall voltage gain of the cascode is basically unchanged: the common gate acts as a current buffer (since the two MOSFETs share the same drain current) so the same current flows through the load resistor as in the common source amplifier (thus producing the same output voltage). However, the lower input impedance of the common gate means that the voltage gain from the input to the drain of the common source MOSFET is significantly lower -- this also reduces the Miller effect and improves the bandwidth. Even though the input to the overall cascode amplifier is a voltage signal the common gate amplifier is useful.