If your lights blind oncoming traffic and cause other vehicles to crash, that's a disadvantage. If your lights cause you to be pulled over by the police, that's a disadvantage. I don't believe 4000 lumens are necessarily problematic, but I can think of plenty of scenarios in which significantly exceeding the output of vehicles around you could produce negative results for you or others around you. Even at a much smaller level, there are certain situations where I don't run my P7 at night. Almost all of these situations have to do with not wanting to stand out (at least until passing certain areas).