It’s also part of how you think about DCs. In terms of a single person (a person succeeding) the dc is pretty high. But when you think of it as the “group succeeding”, with all the synergies that entails, suddenly it’s a different ballgame.
A classic example is a knowledge check. One character getting the check might have a decent chance of failure. But if multiple characters can roll…the odds of success go up temendously. It happens anytime a group can each make a check per person, but only one needs to succeed.