Constantly pinging servers and downloading live data in the background drains battery life significantly. Running the game offline is optimized for performance, allowing you to play longer on a single charge.
Gameloft implemented in MC5 to prevent piracy and sync player progress across devices.
Because the Play Store limits APK sizes to 100 MB. For a 1.5GB game, Gameloft splits the installer (APK) from the assets (OBB). When you search for "modern combat 5 apk obb download offline" , you are looking for a specific modded pair that bypasses the online server check.