You can shred it.
The only time where such paperwork proved valuable was from the days of "Tech Plus" (passed General written but not 13element 3A and 5 WPM code). The FCC eventually reverted Tech Plus to Tech licenses. When the code requirement for General was dropped, former Tech Plus licensees could get "automatic" upgrades to General if they could show paper proof of their former status. This was back in the days when paper, not bits, mattered.