We will need more information to answer your question.
Mobile Hotspot is a buzzword that suggests something is already broadcasting a personal WiFi connection. The mobile part suggests the device is battery powered as opposed to something you plug into a wall. I suppose a car would be pretty mobile so you could consider any WiFi services in your car as a mobile hotspot feature.
Based on what you have provided so far I'd say if you have a mobile hotspot feature then you are already leveraging it for WiFi. Perhaps you are asking about using the mobile hotspot for WiFi only? Meaning that if you deactivate the Verizon service behind it will still function?
If so that is a question for your manufacturer and not something Verizon has control over. Generally speaking when the cellular service behind a mobile hotspot is shutdown or deactivated the device will continue to function as a local only WiFi hotspot. All you loose is the internet connection without a cellular signal to back it up.