"Brevity": why is legal drafting so relevant?

Why is legal drafting so important? Why is it necessary that laws are "comprehensible"? 

In a 1940-memorandum called "Brevity" English Prime Minister Winston Churchill recommended that his colleagues and their staffs wrote shorter reports. Professor Sabino Cassese, while mentioning the above mentioned memorandum, observes how Italian laws are still too many and obscure, and legal drafting is baroque. This becomes pathological especially in times of Covid-19 emergency.

An example is  the  Collection of Covid-19-related rules created by the Italian Civil Protection that brings together in a single document of 295 pages all the interventions published in the last 30 days!  

Overproduction of norms and the need for their legibility have also recently been addressed by several scholars: 

V. Zeno Zencovich, A normative metastasis?

Creating Incentives for Regulatory Comprehensibility - Series of Essay - Repost from RegulatoryReview.org