Line types in Blanket Purchase agreement form 'Goods - no receipt entry' ?

Hello,

There are couple of lines types available while entering Blanket purchase agreements which say no receipt entry.

what is the purpose of them ? ( No receipt entry )

Is there a validation that, if someone chooses a No receipt entry line type, oracle will not allow them to receipt ?

How can i hide them or remove them in our instance ?

As we use 3 way matching and receipt is mandatory for us.

Regards,

Noorie