If you are really good at determining "buy areas" and scale into them, then scale out on the way up, it can definitely work...Obviously the problems occur on the occasions that you are incorrect and you have this very skewed r:r...I've seen plenty of guys over the years who were aggressive scale traders and I believe there is some sort of euphoric rush involved with scaling in and then watching the market turn on a dime and fly higher...It's a very difficult habit to break though...
OTOH, all of my respect is reserved for the traders who do the harder trades which is to add to winners...Whereas the scale trader is going to be aggressively exiting, the other trader is adding...It won't have a great win percentage, but the gains will dwarf the losses if done correctly...So I'd say that "scaling" counter-trend satisfies an impulse that many of us have, but it just takes a handful of poorly timed scales to really blow things up.