Sometimes small things can make a big difference. Like a dot. You can put it at the end of the sentence or in a number (1.001 vs. 100.1 - can make a "small" difference) or you put it into the zero to make it easily distinguishable from capital O.
Now you might say, who cares, but if you read a lot of source code (like I do) Source Code Pro is a real pleasure for your eyes. Give it a try. Highly recommended.
PS: Source Code Pro works with all kinds of IDEs, not only Emacs.