Why unredacted addresses of donors?

You can send out merge letters to all the donors of a PAC.
Such a letter provides the recipient with talking points for the opposing point of view which they may not have considered.

Here is an example of such a letter.

This letter contained attachments as follows:
     A copy of the page of a campaign finance report of their donation
     A copy of the notification by the Texas Election Commission against the candidate or PAC
     A copy of arguments against abortion
     A copy of the dangers of homosexuality