Yes, a buck converter will work very well. Its not as efficient at low currents though.
Advantages:
1. Wide input voltage range
2. Very stable output
3. Generates less heat with high current than linear regulators.
4. Input voltage can be lower than output voltage.
Disadvantages:
1. Large
2. Heavy
3. More expensive than linear regulators
4. Less efficient at low currents
5. Introduces ripple
Advantages
1. Very small
2. Very light
3. Very simple to wire
4. Very efficient at low currents
5. Introduces NO ripple
6. Very efficient when output voltage is near input voltage (as is the case on the phantom to 12v)
Disadvantages
1 Generates lots of heat at high currents
2. Input voltage must exceed output voltage
So, it depends on what you wish to sacrifice as to whether a buck or a linear regulator will be best.
If you are not worried about weight or complexity of the device, go with the buck. If you want the simplest and lightest option and can deal with the dissipated heat, then the linear regulator is your choice.
Since I don't know the current you intend to draw, I really can't say much more. If its very low current, linear again wins. If its high current (amps not milliamps) then the buck will be better if you can afford the weight.
BTW, that one from amazon is way too big and bulky. Maybe this one, or one like it is a better buck option:
Car Voltage Regulator 12v 24 DC Buck Step Down Converter 4-38V to 1.25-36V DC 5A
Its small and light and has an adjustable output so you could use it for anything.