I was told the very same thing by someone else in the lubricant industry many years ago.
I use a LOT of oil in my business for vacuum pumps and air compressors and I can tell you from first hand experience that unless you have a valid reason to use synthetics (such as extreme temp conditions, particularly on the cold end) there's no significant advantage. The big myth is that it provides extented service intervals. While it's true that it will maintain its viscocity over a longer time it will still get just as dirty as any other type of oil. The dirt will do just as much, if not more damage than anything else and the only fix for that is to get it out.
One more thing, I've seen certain synthetics go bad and when they do, it's not a pretty sight. It has a snowball effect. The oil gets a little fouled, the pump runs a little hotter, the oil fouls more, the pump runs a little hotter.......
This can and will happen with any oil but I can tell you that with synthetics once the proces starts it happens FAST!!! The oil gels up and basically destroys the machine it's supposed to be protecting in the first place.
Not trying to scare anyone and I'm by no means an oil expert, just sharing my first-hand observations.