Depends on how secure the application and the security you use in front of the application such as reverse proxies, load balancers, etc. If you are exposing a web application with no SSL, no two factor with, or something in a beta state or if you can’t trust your ISP not to create man-in-the-middle attacks for advertising and collecting information to sell which also likely introduces security vulnerabilities, then that could be a problem and a VPN or similar might be a big help.