It's all relative. A $1750 Copenhagen might be cheaper than a $2900 Trek. I don't care for the concept. Our first ebike was $1300 in 2015 and still runs well, and I think it's a better value. My first ebike conversion was also from 2015 and cost me under $500. It's been quite reliable, but I did have to draw on years of hands on tinkering and engineering knowledge to be comfortable with the project.
I think a Copenhagen is overly expensive and limited in range/speed/climbing compared to a less expensive conventional kit, but the latter requires expertise to install. A Panasonic 10 speed with dropped bars is not the ideal candidate for conversion. The controls, brake levers,and throttle used in most bike kits are intended for hybrids and mountain bikes. The road bike frame is probably overly narrow for a regular hub motor. The Copenhagen would drop into a road bike and there's no wiring,as I understand it. For someone w/o mechanical/electrical skills, that is huge, Nonetheless, you could buy a complete ebike for that kind of money (Juiced, Radbikes, etc) , and you also have to consider what he plans to do with it.
I figure your friend will ride with you. How far and how fast do you ride? I don't believe the Copenhagen will hold 18-20 mph under assist for too long. Lots of hills in Wisconsin too.,