It fits discretionary, level-based trading: if your stop belongs below a swing low, drag it below the swing low. The chart becomes the order entry surface and the position view at once.
Two cautions. Dragging is imprecise near the pixel level, so most platforms snap to the minimum-price-increment and let you type exact values. And an accidental drag is a live order modification, not a drawing edit.
Example: you drag a stop from 98.40 to 97.85 to sit below a swing low. On 300 shares that widens risk from $180 to $345, a 92% increase in risk-per-trade from a single mouse gesture. Good platforms show the new risk in dollars as you drag.
Related: hotkeys, depth-of-market, working-order, cancel-replace