I don't trust myself to PWM the lights directly - if I put the duty cycle a bit too high and an LED burns, ordering another switch will be $25. If I'm only playing with a safe voltage like 2.8, I can't screw it up. Limiting resistors are also out, they waste too much power.
Edit: Oh, okay. I guess I need a current limiting resistor in case the voltage out fluctuates a little bit. I'll add one. But I'm still okay to PWM the transistors as planned, right?