Well, most of the time in my experience people are doing this for a hobby, and a little extra time investment in a project isn't the end of the world, but a price tag might be. I'm notorious for doing things totally wrong but eminently cheap. If you are okay with the fact that recharging a fire extinguisher after finding out that a component really CAN'T handle three times it's rated value is cheaper than buying the component with the proper ratings, then you are a proper tinkerer, in my humble opinion...
All that said, I run MOSFETs with a 100 ohm gate resistor and am switching hundreds of watts of LED's with them. Barely get warm. Darlington pairs were MUCH hotter running and I had to accommodate for all that loss in terms of power supply side too.