Short answer is yes. It lets you put down three units as a single deployment drop to win turn choice and gives a nice durability buff for keeping them near each other (which you were going to do anyways).
Long answer is the battalion won't really be worth it's cost unless you are running at least 80+ plague monks, because otherwise you will be better served by spending the points getting more bodies, because the horde unit discount on Skaven allegiance is so strong. If you are running 80+ monks you probably want to go all-in on Pestilens to get monk battleline so you can cut out the middle rat by putting three 40-man units into a single congregation of filth. So it turns into a chain where you either run full pestilens or are better off just getting more clanrats instead of a congregation of filth.