Unlock bootloader question

[dr-caligari]

Hello!

In your manual, in the unlock section, it says:

1. Erase metadata and userdata (and md_udc if existing):

python mtk e metadata,userdata,md_udc

2. Unlock bootloader:

python mtk xflash seccfg unlock

The question is:

What is the point of clearing partitions from the first paragraph before unlocking?

What is fraught with the implementation of the second paragraph without the first?