If you plug it straight into the network, you need to assign that printer an ip address, and it will require every machine that logs onto it to download the drivers; which sometimes requires an install CD.
If you host it from another PC, then that PC acts as the print server and allows all other PCs on the network to connect to the printer under a share, usually without much effort involved.
I personally like hosting a printer from a PC, though I have done it through a network before. It all gives you the same result.