It's for builders mainly. On a construction site you might not have a wall outlet near every place where you do work and running extension cords is dangerous bo

It's for builders mainly. On a construction site you might not have a wall outlet near every place where you do work and running extension cords is dangerous both due to tripping and to the shock hazard when a cord gets damaged. Many crews used pneumatic tools, which eliminated shock hazard, but cordless is taking care of tripping too. They use multi-port fast chargers and whole bunch of batteries though. Also in automotive, again, even though the workshop has the power (and they traditionally used pneumatic tools), running hoses everywhere is dangerous and annoying, I see a lot of mechanics using cordless impacts and grinders.