Security is the "key" here.
Anything you do on your mobile through VPN is secured using SSL / ESP protocols.
Accessing emails is secured and it's a requirement of a business.
Accessing internal resources by authorized users only - we facilitate that through this feature of VPN on mobile.
The mobile devices are checked to ensure the mobiles are not compromised in terms of root / jail broke. If they are, they are not allowed to login and access any company resource.
If you have any specific question in your mind, make it more precise and clear so that we can give you information in depth.
Hope that answers your question.