The point is they're unexpected. Elo is a great example, people tend to assume this chess rating system is an abbreviation, but it's somebody's name.
It's not unexpected that Ada is named after Ada. It is unexpected that PageRank is named after a person named Page rather than web pages. It may seem less unexpected if you happen to know who Larry Page is, but the same could be said for Glen Bell, if you knew who he was then it's "obvious" why the business is named Taco Bell right?
It's not unexpected that Ada is named after Ada. It is unexpected that PageRank is named after a person named Page rather than web pages. It may seem less unexpected if you happen to know who Larry Page is, but the same could be said for Glen Bell, if you knew who he was then it's "obvious" why the business is named Taco Bell right?