That is 10 megabytes per ruby application per server. I don't know how many ruby instances there are in the world, but the total memory reduction across the world could easily be in the order of petabytes. Small change with large impact.
no disagreement - better to use someone elses - but if your using one tiny part of a gigantic library of functions, it may be more cost effective to find a better (smaller) library, or write your own.