Help please regarding harvester for better understanding

Hi there, so I have a couple of PCs plotting on my LAN and one main node on ubuntu 20.04 desktop with the GUI showing me the status (I don’t use that machine for anything but the full node). That machine has port 8444 portforwarded and working just fine.

Question: I have a 250Mbit/s connection and I am not quite clear why one would need all these different harvester machines so I’d really appreciate if somebody could explain. I have around 300 plots right now and the GUI status is “synced” and “farming”. So:

Q1: why would I need extra VMs as harvesters?
Q2: would there be any benefit of having multiple harvesters on the same LAN or should I get a VPS that can “mount” the folder with the plots (the destination folder) remotely? Other than a possible security risk (I wouldn’t share private keys and the mount would be read-only), any idea whether this would be good or bad?

Would appreciate some perspective here. I feel everything is fine but I saw this script here: GitHub - stolk/chiaharvestgraph: Graphs the activity of a chia harvester in a linux terminal.
… and it’s showing mostly red on my harvester VM…

BTW, I set up the harvester with the SCP CA process outlined by JM here: Chia farming on multiple systems - introduction to harvesters - YouTube

Cheers gang!