The Malleus has a reputation as the engine of the witch trials, and that reputation is older and firmer than the evidence for it. It went through many printings between 1487 and the seventeenth century, which shows there was a market. It does not show what the buyers did.
Historians who have looked at the question directly find the correlation weak. Prosecution was intense in some territories that show little sign of the book and light in others where it was owned. The heaviest waves of trials came a century and more after publication, driven by local courts, local panics and local law rather than by one manual. Julian Goodare and others therefore treat the Malleus as one symptom of a shift in how learned Europe conceived the crime, rather than as the cause of it. Against that, historians who emphasise the transmission of the demonological model note that the book gave later writers a ready-made template and a claim of authority they reused.
Two features of the printed object carry more weight than the argument inside it. A papal bull of 1484, Summis desiderantes affectibus, was bound in as a preface; it had authorised Heinrich Kramer's commission and said nothing about the book, but printed there it reads as papal endorsement. An approbation from the theology faculty at Cologne was printed with it too, and scholars have questioned how much of that document the faculty actually signed.
What is not in dispute is what the book is. It is a source about inquisitors and courts. It is not a source about witches, because there were none.