The cold flow properties are the main reason I usually hear people wanting to use synthetics. At the same cold starting temperature, say 75 degrees Fahrenheit, conventional oils may have a viscosity (thickness) of 100 and synthetics may be closer to 50. If engines are designed for oil with a viscosity of 10, then at startup time, synthetic oils are closer to the engine's design specification and may actually flow and lubricate better at startup time than conventional oils. Since most wear occurs at startup, synthetics theoretically should reduce that wear to some degree. How much wear is reduced and whether it really amounts to anything noticeable over the lifetime of the vehicle is anybody's guess.
The tangible benefits are things like better cranking speed (and presumably startability) at very low temperatures and if the engine cranks better and the engine is lubricated better at low temperatures, there may be some small mileage increase as a result since the starter wouldn't have to draw as much current that the alternator would have to replace. There could be reduced friction before full temperature is reached since the oil's viscosity would be closer to the design spec sooner after starting than with conventional oil. Another tangible benefit is that synthetics seem to have a longer useful lifetime than conventional oils. If getting the oil changed is a hassle, you should need less frequent changes with synthetic motor oil than with conventional, but I would still follow the maintenance minder during the warranty period and only stretch out the interval after the warranty has expired. Fewer oil changes over the lifetime of the vehicle may mean you've put less toxic stuff in the environment overall, and it could save money on oil changes, but the high price of synthetics probably offsets any cost savings in most scenarios.
Notice please the use of the words "could," "may," "might," "possibly," "maybe," and "theoretically." Your mileage WILL vary. I certainly don't have all the facts and I'm not a tribologist. Any ideas here are derived from what I've gleaned from other seemingly respectable sources and I certainly am not presenting any of this as fact. Draw your own conclusions. I'm just pointing out my own reasoning that is likely flawed and fails to take into account all factors. I won't make any definitive statements because motor oil seems to be like religion. The debates and arguments can go on and on ad nauseum, and the end result is people just do whatever they believe or think is best. See the forums at www.bobistheoilguy.com
if you want a good example of people who have way too much time to talk about motor oil. I won't suggest you do anything differently, but hope you might have something else to consider when you make your decision. I reserve the right to edit this post if I find a mistake or learn something new.
Good luck. Your car will probably be fine whatever oil you use as long as you follow the recommendations and specifications in the manual.