"constructing proofs directly by hand" or "directly constructing proofs by hand"

There are two alternatives for a sentence

Nevertheless, developing automatically verifiable proofs by proof assistants usually takes more time than constructing proofs directly by hand.

and

Nevertheless, developing automatically verifiable proofs by proof assistants usually takes more time than directly constructing proofs by hand.

Someone told me that "constructing proofs directly by hand" was better than the other representation, but I can not understand the reason.

Much appreciation to anyone who would like to give me some help!