This is true, but APIs are often versionned. Concerning efficiency this is true CSS / XPath processors, at least, both offer very nice performances. But downl

This is true, but APIs are often versionned. Concerning efficiency this is true CSS / XPath processors, at least, both offer very nice performances. But download 70KB of HTML each time you only need a single data, where the API request cost only a few (avg < 2KB), can be such a pain if you need to do this frequently. This can be handled by a scalable configuration but I find it a bit the overkill.