Why do some traders move the stop loss to the cost line soon after the floating profit of the order?

First, you can guarantee that the transaction will not lose money. Second, most of the position opening points are support points or resistance points. When the price returns after making a profit, it is very likely that the market will reverse. At this time, the stop loss can be left to wait and see.

It cannot be generalized.

If you rely on the support level to go long, don't raise the stop loss. The stop loss position is the position where you expect the support to fail, and once it is raised, it loses its meaning.

If you follow the trend and add positions with floating profits, I will let the cost line after the increase be below the strong support level, and at the same time use it as a stop loss point, so that the worst result is no loss and no profit, avoiding psychological blows.

In short, it depends on your billing position and logic. If after placing an order, based on the follow-up trend, you feel unsure, you can go straight away, or set a guaranteed loss, which is a good choice.