Updating the ZTE MC7010 firmware offers several benefits:

Generally, no. Carriers lock the bootloader and firmware partitions. Flashing generic firmware will usually result in a "Software Mismatch" error or a bricked device.

Some ISP-specific firmwares lock out certain FDD (Frequency Division Duplex) bands. In some cases, this is a hardware limitation where the physical components for those bands are missing from the board.