If you have the CPU, RAM, and disk space, you should leave these settings on.
It will affect some client versions' choice of guards: https://trac.torproject.org/projects/tor/ticket/24312#comment:4
I have guards that are bottle-necked by CPU, and I'm still exploring various options in response to DoS and extra load.
It seems like "DirCache 0" isn't the best option in this case, since modern Tor Browser clients will not choose a guard with "DirCache 0".
For now I will utilize other options that have been discussed here.
Thanks for the info!