To each his own I guess. I'm a retired engineer and like to work with statistics. IMO, one can't have too many screens. I use four:
View attachment 76844
Two are GPS receivers. One displays the ride stats with big numbers I can read with my old eyes and the other displays a rolling map large enough to read details while navigating. The ride details are saved & downloaded to my desktop. The third screen is the bike display set to show speed, PAS level & battery gauge. The fourth is a smartphone (out of it's mount & being used to take the pic). I use the ESB app on the smartphone to display battery voltage, % charge and remaining distance on the current charge. The screens on all the devices are programmable and able to show a variety of stats.
Sure, I can combine all the information on fewer screens but for me, the resulting numbers are too small to read at a glance.
What can I say, I'm just a geek at heart.