@ohluckyirish
Heh...everyone has an opinion so I might as well throw my two burritos in!
Short answer...PanelDue is not needed, but I have found it to be very useful.
I use my LapTop via the WebConsole to control the printer, but I use the PanelDue for ancillary tasks and status reports.
If on a budget, you can get along without it, but, it is useful and is convenient at times. Like seeing what (DHCP) IP the DUET controller has been assigned.