You're correct. It isn't a direct solution. For the most part, it makes the selection experience easier, which then makes the editing experience easier.
But I wouldn't underestimate how big a difference it is. One difference between a folding phone and an iPad, is that I can reach every part of my screen with my thumbs still in their resting position. It feels a lot more ergonomic to have an 8 inch 4:3 screen than a larger 16:10 screen that requires hands gymnastics to touch type.
Hold to select word. Drag to extend selection. Drag pops up the edit menu by default, which takes little screen real estate and zero additional clicks to do a cut/copy. Lastly, a cut/copy automatically puts the snippet as the top recommendation on my auto complete bar on the keyboard. So paste doesn't need triggering the edit menu again.
Samsung doesn't have a double tap experience. So it removes that ambiguity.
I have the stubbiest fingers I know and I type a lot ; as my HN profile bears witness. So I have heavily user-tested this experience that I claim to love so much.