example:

you limp in EP with 6,7s; 4 others limp. You hit 4 to your straight, but can't do anything because you have 4 others behind you. You check, Last limper raises, you don't have position so you may need to fold.

NOW, you limp at the button w/6,7s; 4 others limp in front of you. Same flop. If checked to you, you can decide to check to get a free card or raise to semi-bluff the pot down or see a free turn card when the callers check to you next round.

Same cards, same flop, better result.