If your audience is coming from an Excel heavy and classic BI world, they will be asking pivot tables all the time, no matter how many charts you do for them in Tableau. I believe this is a transition phase that many Tableau implementations go through and you have 2 choices:
- You say no and your users will probably end up duplicating your work in Excel just to do pivot tables themselves
- You say yes and you make it better than Excel while you start nudging them towards a more graphical approach
I usually go for the second option of course.