Surveillance law is a pretty relevant example, since for most people not on HN it's a relatively low priority, and there's a fairly high likelihood that if they're able to delegate somebody to vote for them on a general area like "civil liberties issues" (for most people, a delegate with a decent libertarian credentials) and "national security" (for most people, a delegate who promises to be robust), the person or committee that decides for whether a particular surveillance bill is considered "civil liberties" or "national security" in effect holds a casting vote any time most of the public doesn't feel strongly enough to make a bill-specific decision. Somebody has to resolve differences between a budget balancing bill popular with the public's preferred delegates for "taxation" issues and a bill with public spending implications popular with the public's preferred delegates for "health issues", "education issues" or "social policy issues" too. Since they're supposed to be administering a process rather than enacting a particular programme of government they were elected on like a de jure executive, they're probably also subject to far less scrutiny.

Of course, the system still has the advantage that the public can step in and overrule their regular representative whenever they feel strongly enough to do so, but not necessarily any more effectively in practice than powers to force a referendum as a form of public veto.