This statement assumes that god authored the bible, and/or that those who passed on oral traditions, copied the written versions and finally edited and redacted in the years before Jesus reflected what this god thought.
Why is it important to JW's and others who insist on using the name to differentiate God by using a name?
IMHO, calling God Yahweh, or YHWH, was to differentiate him from other gods; it is really a tacit admission that the Israelites were not monotheistic throughout their history. The use of el, as in Bethel, Israel and other names and places like it show the influence of El on the Israelites; after a time the names changed to Isaiah, Jeremiah, etc, with names consistent with Yah.
The second thing I think is that the witnesses constant use of Jehovah softens the shock of what they hear from the platform and what they think to themselves.
As in this:
The faithful and discreet slave, through the governing body, are Jehovah's channel of communication. This sounds less radical than saying God speaks through the governing body.
Jehovah will sustain you vs God will save you.
My 2 cents.