Ok, let me explain it to you this way. Let's say you have 12V, a LED string with a Vf of 10V, and a 100Ω resistor in series. This means that there will be 2V across the resistor and 20ma will flow. That will mean there is 40mW wasted in the resistor.
Now, let's say you have 14V, a LED string with a Vf of 10V, and a 100Ω resistor in series. This means that there will be 4V across the resistor and 40ma will flow. That will mean there is 160mW wasted in the resistor with no PWM. Now if we PWM it at 50% that means that an average of 80mW would be wasted in the resistor and an average of 20ma will flow.
If you have 14V, a LED string with a Vf of 10V, and a 200Ω resistor in series then there will be 4V across the resistor and 20ma will flow. That will mean there is 80mW wasted in the resistor with no PWM.
As you can see, there is no power saving using PWM without an inductor.