Legitimate uses include: repairing a phone you bought legally, recovering after a bad flash, or working as a certified technician restoring devices to factory specifications.
for deep technical discussions on MTK NVRAM backups and common pitfalls (in Russian). Read about repairing IMEI on MediaTek devices Mtk Nvram Editor Tool
: Restores corrupted WiFi and Bluetooth addresses that prevent the device from connecting to networks. Backup & Restore Legitimate uses include: repairing a phone you bought
: Fixes "Invalid IMEI" or "Null IMEI" issues that often occur after flashing a new ROM or a failed software update. Connectivity Fixes recovering after a bad flash
How to fix IMEI using nvram.bin & nvdata.img in MTK - Hovatek