Question 3: The speaker would avoid biographies of all other scrivene…

Read the following passage and answer the given subquestions
I am a rather elderly man. The nature of my avocations for the last thirty years has brought me into more than ordinary contact with what would seem an interesting and somewhat singular set of men, of whom as yet nothing that I know of has ever been written:—I mean the law-copyists or scriveners. I have known very many of them, professionally and privately, and if I pleased, could relate diverse histories, at which good-natured gentlemen might smile, and sentimental souls might weep. But I waive the biographies of all other scriveners for a few passages in the life of Bartleby, who was a scrivener of the strangest I ever saw or heard of. While of other law-copyists I might write the complete life, of Bartleby
nothing of that sort can be done. I believe that no materials exist for a full and satisfactory biography of this man. It is an irreparable loss to literature. Bartleby was one of those beings of whom nothing is ascertainable, except from the original sources, and in his case those are very small. What my own astonished eyes saw of Bartleby, that is all I know of him, except, indeed, one vague report which will appear in the sequel.
Ere introducing the scrivener, as he first appeared to me, it is fit I make some mention of myself, my employées, my business, my chambers, and general surroundings; because some such description is indispensable to an adequate understanding of the chief character about to be presented.
Imprimis: I am a man who, from his youth upwards, has been filled with a profound conviction that the easiest way of life is the best. Hence, though I belong to a profession proverbially energetic and nervous, even to turbulence, at times, yet nothing of that sort have I ever suffered to invade my peace. I am one of those unambitious lawyers who never addresses a jury, or in any way draws down public applause; but in the cool tranquility of a snug retreat, do a snug business among rich men’s bonds and mortgages and title-deeds. All who know me, consider me an eminently safe man. The late John Jacob Astor, a personage little given to poetic enthusiasm, had no hesitation in pronouncing my first grand point to be prudence; my next, method. I do not speak it in vanity, but simply record the fact, that I was not unemployed in my profession by the late John Jacob Astor; a name which, I admit, I love to repeat, for it hath a rounded and orbicular sound to it, and rings like unto bullion. I will freely add, that I was not insensible to the late John Jacob Astor’s good opinion.
Source: Bartleby, the Scrivener - Herman Melville

The speaker would avoid biographies of all other scriveners for a few passages about the life of Bartleby because ________________.