I thin the larger the group you are training with, the longer the total time in breaks.
When I'm doing a long run by myself, if I need to use the bathroom, I just duck into one quickly - I can be done in less than a minute. But when you have a group that stops at the bathroom, you need to wait for each person to take their turn. If you're running in a group of 6-7 people, that can add up.
And then of course you get a few miles down the road and the one person who didn't go before realizes that he/she needs to go now, and that's another break. And so on and so forth.
As others said - if it's just a time on your feet at easy pace run, I really don't worry about it. For long runs with quality in them, I think it's much more important to limit or eliminate the breaks during the quality part. I sometimes see people do workouts that consist of intervals of 2-3 miles at marathon pace with 1 mile recovery....except that after each interval they stop their watch, do some stretching, hit the bathroom, refill their water bottles, and then start the one mile recovery. And they can't figure out why the paces they hit in those workouts are not reflected in their race performances....
For myself, if I need to stop for the bathroom or water or shoe-tying during a marathon pace workout, I keep the watch running. Just like the clock would keep running in a race.