Basically the same, except:
a) An insert can be specified during creation of an FX track.
b) The channel is named with the chosen insert effect.
c) FX are added to the FX folder when created.
d) Groups are added to the Group folder when created.
c) They are classed differently for visibility in mixconsoles. For example, you can show/hide ALL the FX channels separately from the group channels, and vice versa.
If these differences don’t mean much to you, because you name all tracks explicitly and you put your group/FX tracks in different places according to your visual routing association needs, you will probably be able to forget about using FX, in favour of using only groups. That way, you can build up a routing hierarchy and just insert FX in whichever group suits your purpose.