5400 RPM HDD vs 7200 RPM HDD vs SATA SSD

I recently replaced my antique Toshiba laptop with a new shiny new HP, which I freely
admit is at least partly a toy since I'm retired and do my real work on a PC. The
new laptop arrived with a 1TB 5400 RPM HDD. I added a 250GB NVMe SSD to use for the
system drive and set up 2 partitions on the HDD, E: for working data and F: for
storage and backups. I'm planning to replace a memory module and go from 12GB to
16GB total (not much difference, but I'm prejudiced against uneven modules in twin
slots). While I have the laptop open, I could change the current HDD to something
else like a 7200 RPM HDD or preferably a SATA SSD. But my thinking is that I'd not
notice much difference in day-to-day operations since the system drive wouldn't be
affected. System backups would probably go noticeably quicker getting sent to SSD,
but no real need to upgrade unless there are obvious improvements beyond that. Is
there some aspect I'm missing here that might justify an upgrade? Please! I can't
come up with anything no matter how hard I try.

Larc