From the JSTL Specification itself:
"Many web applications need to access relational databases as the source of dynamic data for their presentation layer. While it is generally preferred to have database operations handled within the business logic of a web application designed with an MVC architecture, there are situations where page authors require this capability within their
JSP pages (e.g. prototyping/testing, small scale/simple applications, lack of developer resources)."
In other words: using the SQL actions for quick-n-dirty prototypes may be OK, but don't use them in anything "real".
JspFaq