Gmail web offline

Gmail has the ability to use a technology called service workers that allows the site to work on the browser even when internet access is limited or non-existent. Enabling Gmail web offline will allow the members of this organization to use this feature from browsers.

Having this enabled is highly advisable because it will enhance the experience for your users and will prove particularly useful when having any kind of connectivity problem or limitation.

Enabling Force deletion of offline data on sign out of Google account is also recommended. This will erase all the information stored on the device when they log off, so they don't need to worry about cleaning the cache or leaving sensitive information:

Being able to use Gmail offline without the need of installing any app makes things easier for your users when on the go, it allows them to use their commute time to read emails or work on drafts even when data is not reliable, such as when using the subway.