The VBIOS has very low risk of issues as long as you use the bios made for your model number. The biggest risk is the power shutting off as it updates.
If you have integrated graphics, and a VBIOS update fails, you can usually refresh the bios to recover the card.
If you have an dual bios model, you can load into one bios all the way into Windows, switch the bios position, flash the second Bios chip, and then restart. This is useful if a flash fails, because you can keep one stock/working bios loaded on the alternate bios chip at all times, and then easily recover the other bios.