I use it all the time.
For example, say I have an image in the main timeline with some effects and tranformations and I need to extend the edges of the image I can precompose and leave attributes, then in the new comp make the composition larger. This helps for effects that get cut off by edges.
Or if I have a single image layers that has some effects and transformations but I want to add a fog layer or something to the shot but don’t want to lose control of my keyframes and ainimation, you can precomp and leave attibutes then in the new comp add a bunch of layers.
or instances where you may not have effects but that the layer is parented or linked by expressions to other layers in the currect comp, and standard precomposing may break the purposes of these connections.
Anyways… I hope this gives some ideas
Andrew