"Hand off straight up the middle for none yards; it will be second and ten anyway."
Yep, I don't like it because it's too predictable. We run on almost every 1st down, although it does appear they're trying to mix it up a bit more lately.
But the idea behind a grindy run game is to keep doing it again & again, for long periods of time. This theoretically does three things:
1) Tires out the opposing D.
2) Lets you figure out the opposing D's weaknesses to then exploit.
3) Eats up clock.
This is why Dallas has often been called a "2nd half" team, as this process is an investment that doesn't pay off until further into the game.
Does it work? Meh, sometimes. Seems the league overall hasn't used this for over a decade, but that doesn't mean it can't work this year...