To keep future readers of this thread from missing the underlying point here…
We’re all very much aware of the usefulness of having human-readable permalinks. Most of us do enable custom permalinks on our blogs, and not because it’s cool! The original question was whether this:
/2000-honda-civic/
or this:
/2000-honda-civic.htm
is the better option. But look at them, up close. How is sticking .htm on the end of some virtual url making it better, or more “human readable,” or in any way improving over the standard WordPress permalink structure most of us use?
In one sense (at least from a support perspective), the latter is worse, because WordPress does a lot of things internally that have to assume a directory structure. Imagine providing pagination to a post. How does that human-readability factor come into play for something like:
/2000-honda-civic.htm/2/