^Buying Bitcoin with lump sum is the best strategy but the problem is not everyone can afford to dump at once which is why DCAing is very effective for accumulating Bitcoin even for the retailers. And also I wouldn't say selling at high is wrong because that's the basic of making profits by selling an asset while we can't really draw the line which is high and which is low due to the highly volatile nature so all we can do is just go with the instinct and try to make best out of it.
Every strategy in bitcoin investment is good for accumulating bitcoin, and if we must single out the best strategy for accumulating bitcoin, I think that should be the DCA strategy. The reason is that it has proven to be effective in accumulating bitcoin, and it has also helped so many investors who think that it's too late to invest in bitcoin to get started with their bitcoin investment, and they are consistently accumulating bitcoin either on a weekly or monthly basis.
Depends on strategy since not all is actually working and it will matter depends on the understanding of the person who execute it and how consistent they are the way how they deal with their investment.
That's why instead of thinking about short term or anything related to trading, they better choose to stick with these method especially if they want to deal with Bitcoin since there's provably more better future coming ahead with them and they won't get stress out following market tracks which commonly been chased by trader. Provably those thinking about they are late or anything will be eliminated especially if they are on process of accumulation especially when planning their next action and for sure they enjoy the whole process especially if they could see their total volume bought grows more.