I haven't really had much use for the LCD since I started using the OctoPi. I haven't even used the SD card. While the print is running from the OctoPi, the only info the LCD gives is temperature and location. I do use the LCD knob, though, to resume a print if my filament runs out and triggers a pause switch, though I could do that with any momentary switch, I think. Now you've got me thinking about removing my LCD. As for a display being required for the Raspberry Pi, not necessarily. I access my RasPi over wifi from my Ubuntu laptop. I open a terminal and SSH into the RasPi via its router address. Then I can do the setup from my laptop (only because I have zero hdmi-capable displays in my home, and I didn't want to buy any).