Yes, during the work day, many people would like to commit their changes, often during the same timeframe. Every step takes a second or two, so there's plenty of room to get conflicts (I moved closer to the git server, so now I have an advantage!)

CVS was nice(ish) since changes were independent, any number of people could check in code to limit of io parallelism. Svn was nice, the server would wait for a lock and if my changes didn't conflict, they would be applied after the rest of the pending commits. Git is a PITA, large companies build elaborate systems to queue commits, but we're not big enough to use that yet.