So folks if you try the Krita Next builds from here. You would find a new Magnetic Selection tool which is similar to the one Photoshop has. Here is how it works for now.

The first thing to note is, it no longer works like the PS one, and what I mean by it is, fundamentally both do the same thing, but the User Experience or the UX is different. In Photoshop,

We click on a image and make an anchor. Beware I use point/anchor in the post interchangeably, don’t worry both mean the same thing. Then hover around the edge present in the image and the selection sticks to the edge. We keep on selecting, until we complete the selection by clicking on the initial point which we made in the Step 1.

In Krita,

You make a point by clicking on the image, similar to Photoshop. Then go on making points like the polygon selection tool, and the path automatically sticks to the edges present in the image. We can either click on the initial point to close the loop and press Enter or simply press Enter to make a selection, we will call this the manual mode, just for clarity.

Or,

You press on a part on the image. Then drag the mouse while keeping your left mouse button pressed, along the edge. Release the mouse when done, the path would automatically stick to the edges present in the image Now we can either click on the initial point to close the loop and press Enter or simply press Enter to make a selection and we will call this approach the interactive mode.

Now the craziest part is both of the approaches can be used interchangeably, in whatever way we want. Both will result similar kind of selections depending on how you place the points in the first approach, since the points are placed automatically by the algorithm in the second approach.

Note: We can also create a selection after closing the cage by clicking on the initial point one more time.

But what is the reason of creating anchors? There is not only one reason but a bunch of them, well in short cause they are editable,

To delete an anchor you can either double click on the anchor or click drag it out of the canvas.

The path can be adjusted by selecting and dragging the anchors.

We can also add new anchors in middle by double clicking in the empty space but this is only available after completing the cage by clicking on the initial point.

by clicking on the initial point. We can undo the points by pressing Shift+Z this would delete the last anchor that we made.

And to cancel a selection just press Esc , it would remove everything and start from scratch. Rest of the functions are similar to the other selection tools like the Outline Selection Tool, so we can just refer to the manual for the rest like adding to the selection and deleting from the selection.

https://youtu.be/5M1OJ8jaY1M

Now, since UX is out of the way, Magnetic Lasso, gives us 4 options to play with in the Tool Options docker, as seen in the Screenshot,