Chess is not draughts

"I used to play checkers with her all the time."

"You used to play what with her all the time?"

"Checkers."

"Checkers, for Chrissake!"

"Yeah. She wouldn't move any of her kings. What she'd do, when she'd get a king, she wouldn't move it. She'd just leave it in the back row. She'd get them all lined up in the back row. Then she'd never use them. She just like the way they looked when they were all in the back row."

- JD Salinger, The Catcher In The Rye

I was reading through yet another book - my sixth, I think - on the Semi-Slav, Reinaldo Vera's Chess Explained volume on the Meran. I could hardly help noticing the following sequence, occurring in his illustrative game Krasenkow-Erenburg (Vlissengen 2006) and sundry others. The opening moves, which can be played in a variety of orders, go like this

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.e3 a6 6.c5 Nbd7 7.b4 g6

leading to the following position:

Why, I wonder, do people do this? Why do they deliberately put all their pawns on squares of the same colours? Is it because they can? Is it because they think they're good enough to get away with it? If they're going to do it, why not do it in four moves instead of taking seven? What, indeed, is the quickest time any professional player has taken to get all his or her pawns on the same colour?

I dunno. Maybe they just like the way they look.