Yes, I believe writing a book can help. I do believe how it is published does have some bearing on its legitimacy overall. If your book is through a major publisher, it is going to hold more weight then something that might be self-published. That’s not to say that is self-published book doesn’t contain excellent information, but you have to realize the majority of people aren’t going to read more than the first chapter of your book, and its cachet with them lies in how it was brought to market.
In 1999, I was working for a software development consultancy in Minnesota. The president of that group was asked by Oracle Corporation to write one of their books, specifically on web-enabled databases. This was a big thing at the time, in very few companies have the competency level that we did. Any time that we went out to pitch business, we dropped off a copy of our book on the desk of the CEO for CIO of the company. We had no expectations that the book was going to be read, but it was a lot better than dropping off a few sheets of sales lit in a folder. We didn’t win every pitch, but for the Midwest we would consistently put in shootouts with companies much larger than ourselves, including some of the big accounting firms.
Assess the situation, see what your publishing options are, and then make that decision.
I think it depends on a variety of factors.
Since you are selling B2B and are targeting managers and business people the question is whether you need to convince them of the value add your product brings. If you do, a book might help. But only really if it becomes well known enough so that your target customer thinks s/he should have read it....
I say "thinks they should have read it" because most will not have read it. And most don't have the time to read it. So what you really are using the book for is as a way of creating FUD in their minds that they might need your product, thus opening a selling opportunity.
While a book has more credibility than a blog, it also gets a lot less readership. Another approach that Ive found has traction - is to find a company that wants your expertise to write some white papers for them. White Papers that you can reference carry more credibility than blogs and will get more readership than a book