Lasso Tool & Polygonal Lasso Tool

I don't have the Polygonal Lasso tool in any of my toolbars, because, like Conrad has mentioned, you can do everything with the ordinary lasso tool plus the Alt/Opt keys, which makes for a more fluid workflow. 

It gets a bit finicty when you want to remove from a selection, but it is still doable.  Hold down Alt/Opt and click anywhere inside or outside an existing selection. Release and reapply the Alt/Opt key, and keep it held down as you click each point around the area you want to remove.  When that area would be contained within a straight line to current cursor position and the starting point, realease the Alt/Opt key and it will automatically complete the remove area.

They might have offered both for simplicity and clarity, especially for newer users. Although you can hold down a modifier key to make the Lasso tool work like the Polygonal Lasso tool, sometimes it’s easier to just grab the Polygonal Lasso tool.

There are other examples of this in Photoshop…

The Edit > Transform submenu has commands like Scale, Rotate, Skew, Distort, and Perspective. But technically all those commands are not necessary, because you can do all of those with the Edit > Free Transform command already…if you memorized the modifier keys that do them. If you’re a new or casual Photoshop user, you probably haven’t memorized those keys so it’s easier to just pick the command you need.

The Tools panel has Rectangle, Triangle, and Polygon tools. But you could do them all with the Polygon tool by setting it to the number of sides you need, so the Rectangle and Triangle tools are technically unnecessary. Again, though, a lot of people find it easier to have dedicated tools that are already set up to do rectangles and triangles.

The polygonal lasso tool is much easier to zoom in & make precise selections & edits. I haven't been using the iPad version of Photoshop because it didn't have the polygonal tool.