Before installing a suspicious APK on your main phone, install it inside the virtual KitKat. If it contains malware, it can only infect the virtual machine. Simply delete the VM to wipe the malware.
Running a 10-year-old OS inside a modern VM can be laggy if not configured correctly. Follow these tweaks to make Vmos Pro Android 4.4.2 run as fast as native hardware.
Android 4.4.2 predates many modern protections: SELinux in enforcing mode was nascent, app sandboxing and permission handling were less restrictive, and many known vulnerabilities remain unpatched in unmaintained builds. Running KitKat in VMOS Pro reduces exposure to some threats because the host enforces its own security boundary, but risks persist:
Minimizing risk requires treating the guest as an isolated, controlled environment: restrict sensitive accounts, keep network access limited when possible, and avoid using the guest for banking or other security-sensitive tasks.