It's weird because the IRS Form 1040 instructions say this:
Daytime Phone Number
Providing your daytime phone number
may help speed the processing of your
return. We may have questions about
items on your return, such as the earned
income credit or the credit for child and
dependent care expenses. If you answer
our questions over the phone, we may be
able to continue processing your return
without mailing you a letter. If you are
filing a joint return, you can enter either
your or your spouse's daytime phone
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf at page 76.
But the IRS has also stated this:
Taxpayers should remember their first contact with the IRS will not be a call from out of the blue, but through official correspondence sent through the mail.