What's the difference between the Subdivision Surface modifier and the edit mode->RMB->Subdivide option? Sorry for the newbie question.

I'm following the famous donut tutorial for blender 2.8.

When I press the apply button for the subdivision surface modifier to the torus it makes more vertices + faces for the donut. However, when I press the subdivide option after selecting all vertices of the donut in edit mode, it seems like it's also making more vertices + faces for the donut.

Are these two options interchangeable?

Thanks in advance!
"Modifiers are automatic operations that affect an object’s geometry in a non-destructive way. With modifiers, you can perform many effects automatically that would otherwise be too tedious to do manually (such as subdivision surfaces) and without affecting the base geometry of your object."
https://docs.blender.org/manual/en/latest/modeling/modifiers/introduction.html

If you want to preserve the mesh for ease of use, Modifiers are the way to go. if you don't care about it they are not that different except more options before applying the modifier