What is the difference between the fill command in PS and creating a fill layer?

The fill command is to directly fill the pixels in the image, and creating a fill layer is to create a new layer to fill. The biggest difference between them is that the filling layer is a reversible operation, which can be repeated when it needs to be adjusted, and can be directly hidden or deleted when it is not needed, without any damage to the image. The fill command is an irreversible operation, and it is very troublesome to modify or return to the initial state (if it is beyond the scope of history, of course, it can be solved by creating a new snapshot, but it is not as convenient as filling the layer).

Click the link between the layer and the mask to cancel, so that the limited range of the mask will change, and the general operation needs to be linked, so as to ensure the accurate restriction of the mask on the image. I wonder if I made myself clear.

I hope my answer is useful to you.