Care For A Snoot, Honey?
The 5º grid throws a much smaller circle of light than the 10º grid. They are both somewhat of a soft edge to the light - perfect for highlighting faces in portraits or products on a table.
The snoot also restricts the blast of light but does so with a sharper edge and more artifacts in the light pool.
Note that all of these devices absorb light and radiate it back as heat but the grids are generally buried in the front of the reflectors while the snoot is right out there ready to get you on the forehead as you move through the darkened studio...
If you are a speedlight shooter have a look on the HONL rack in the shop - they also do small versions of the grids that you can velcro on to portable flashes and they have a very neat foldable snoot that does not become hot.