MCT8315A: Not using internal BUCK/LDO Regulator

Hello team,

My customer is considering to use this deivce, and they have several questions.

Q1
Customer don't want to use BUCK/LDO Regulator. (marked as below)
Can they just not use it? OR is it used for internal power supply?

They don't want to place external inductor because of board size.

Q2
If not using BUCK/LDO is acceptable, then Can customer short SW_BK and FB_BK?
Also which register value should customer set for Buck Voltage selection?

Best Regards,
Kei Kuwahara