Why do I need to install the Dashboard plugin?

Hi,

I’m wondering why I need to install the WPMU Dashboard plugin. I have *a lot* of sites and I might want to use some of your other plugins on some of them, but I don’t really want to have to install the Dashboard plugin on *all* of them as this just created a lot of extra work for me. I also experience a slow down in the back end on sites I have that use additional management plugins.

Can you explain what are the advantages and disadvantages to using it are please?