Download a Native app and a web based html5 app and have a play with both. Put your device in airplane mode to see the worst case scenario. To run a Mobile Web-based app (which is essentially a mobile website), the user commonly has to access the Internet via Wi-Fi or cellular connection. Native Event Apps®, on the other hand, reside on the device itself; they don’t require an Internet connection to work. This is crucial because in a hotel or a convention centre you may have hundreds or thousands of attendees trying to access Wi-Fi or cellular network simultaneously to use their Event Apps®, email, social networks etc.
Even with the best venue supplied Wi-Fi service this can produce a virtual traffic jam. Native apps do require updates periodically but those updates usually take less than 10 seconds.
Native apps provide a greatly enhanced user experience. Have a chat with your venue and event app developer to understand what internet access capabilities your venue provides?