I have been known to say that Chip Kelly's Philadelphia Eagles offense is all smoke and mirrors. People should understand that when I say that I am not being dismissive. One of the best ways to win has always been to convince your enemy that they are losing. "Psyops" are among the oldest tricks in warfare and morale, or the will to fight (see 2014 Dallas Cowboys), is arguably the most important attribute of a strong unit.
The party line is that Kelly's offense is predicated on running as many plays as physically possible on the theory that more offensive plays are better. I don't really buy this explanation because I don't believe speed of play is the biggest obstacle to running more plays. Converting third downs is. Furthermore, if Kelly was that dedicated to "more plays = better" he'd be obliged to go for any reasonable fourth down conversion. Yet the Eagles still employ, and even use conventionally, a punter.
But a flurry of aggressive attacks, even if ultimately unsuccessful, can leave opponents stunned, confused, or searching for somewhere to hide until the nastiness passes. There's even a cliché: "back on your heels" to describe what such a series of attacks does. In the movie Excalibur, Arthur's Knights of the Round Table ask how they are to win against Mordred's far superior army. Arthur says they will "use the old ways: speed of horse!" and the knights proceed to gain the victory by using the English fog and quick gallops to convince their enemy that they have more knights than they really do.
It works in real life, too. Robert E Lee at Chancellorsville famously sent Stonewall Jackson's men to attack the Union army from behind, leaving only a bare bones force to face General Joseph Hooker's front line. Lee's forces fought so hard that Hooker refused to believe reports of a large body of Confederates flanking his troops and they were surprised and crushed. Texas history also has the example of the Battle of San Jacinto, which secured Texas independence in similar fashion -- attacking a much larger force when they were overconfident and unprepared, leading them to believe they were losing, and give up. Similar aggressive action allowed Corporal Alvin York and seven other soldiers to capture 132 German troops in World War I and, more recently, Captain H R McMaster to take the nine tanks of E troop, 2nd Armored Cavalry Regiment, and defeat over 80 Iraqi republican guard tanks without loss in operation Desert Storm.
Brock Lesnar and, with less success, Kimbo Slice, both built mixed martial arts fighting careers around this style as well.
So, it's a valid approach. One can only imagine getting pushed around by a 330 lb offensive lineman only to look up and discover you must retreat 20 yards, set up a new defensive position, possibly take a single breath, and do it again on repeat. Even if the other team doesn't score, the chances of being tired, beaten, and most importantly, feeling tired and beaten are very high. It's possible to feel like you are losing when you are winning. It's possible to feel pressure to match the pace and performance of the opponent. It's possible to press and, in short, panic.
Dallas would seem to have the perfect antidote in its ability to control the ball (so long as the turnover flurry of week 1 can be avoided) and Jason Garrett's consistent, level headed, "the next play is the only play that matters" attitude. But it's easier said than done, and, with an Eagles team designed to test that philosophy to its limit, the team will have to be ready to perform.