What is the difference between a pocket WiFi and router?

[Stardom22]

For now l posses the pocket WiFi. However l have noticed that it's somehow expensive because the rate at which the internet bundles are being consumed is very high. So how does it differs with the router concerning the bundle consumption if all factors are constant.

 

[eLdavis]

I think the major difference here is the fact that a pocket wifi is smaller and let's you carry around with ease.