The real deal is that an incandecent bulb is close to a "point source" of light. It throws light off in ALL directions, and you can do anything that you want with it -- including using reflectors to generate a nice tight beam.
LEDs, on the other hand, come "pre-packaged." Due to the way that they are made, they only offer illumination over 180 degrees, max. Because they are encased in a tomb made of clear plastic, the shape of the LED housing can form a sort of lens. This means that LED light is not the "blank slate" that you get with an old-fashioned bulb.
Note that, with clever engineering, the package of the LED can serve to focus the light nearly as well as a reflector. But one problem with this is that the LED die (the chunk of semiconductor that glows) can be somewhat large when compared to the size of a xenon bulb fillament. This provides a sort of upper-bound on how well they can be focused. But, using clever engineering, LEDs are catching up!
Also, keep in mind the advantages of an LED light: relatively constant color (no "yellow beam of death'), more reliable, can be more efficient.