On the other hand, that is exactly the point of a REPL (Read Evaluate Print Loop), like as perl -de1.

There is a time and a place for everything -- but times when you should eval unchecked user input are fairly rare rel to the number of times that it looks like it might be a good idea.

For example, interactive agents of mine often have an "evaluate this" command... but only if they are single-user, or first check if it is me.