EAG scooped that car up from some dealer in MI for 75 grand and sold it for 150.
if you watch any of the EAG videos on youtube you will understand what kind of people buy those kind of cars from them. Its usually filthy rich people with multiple collector grade cars in their stable and owning mint examples is what gives them the satisfaction, not driving them. His clients routinely trade in previously purchased EAG cars for other rare BMWs. That is why he has so many "repeat visitors" and makes money on the same car over and over and over again. Those cars go from collector to collector in enclosed trailers without seeing any significant miles and EAG makes a profit every time it switches hands. Those sub 20k mile cars probably have had more previous owners documented in carfax than the average 100k mile E39.
You are correct in that if you start daily driving that car, the value will drop like a rock but that is not the kinda future that car will have. Unlike the 90k LSB M3 that sold on BaT and the owner plans to triple the mileage in 3 years which in my opinion is an idiotic decision. If you're going to spend 90 grand on a LSB E46 you store it in the garage and preserve its value. If you want to DD a LSB with zero door dings then get a low mileage basic color E46 and spend 10 grand on a quality LSB paint job and you'll save 50 grand and still have a LSB with perfect body panels.... To each his own though