2010 27" iMac as monitor for new Mac Mini?

I have a 2010 iMac that I don’t necessarily want to pitch, but I can’t update the OS due to age. I was thinking of getting a low end Mac Mini as a semi-replacement.

  1. Do you think it would be worth it to connect it to the iMac using to Target Display Mode? I only do normal things on the computer - no need for fancy graphics.
  2. Is the best way to connect using Thunderbolt 3 to Thunderblot 2 converter?
  3. Other suggestions to keep the old lady iMac?