if you are using bind_columns (which is, after all, the fastest way to fetch), then this is fine

That's a reasonable example. It's still slower at the database level, though.

You want to display a table to examine it's structure visually, without knowing its structure in advance.

Looking over the structure of the data falls under interactive use (though you're probably better off using something like MySQL's describe [table] command), which is the reason why SELECT * works at all.

If you're writing code for a real application, you ought to know what the columns are. If you don't, look them up. If you can't look them up, you've got other problems (either poor documentation or bad internal politics). The only exception I can think of to this is when you don't know what table you'll be using in advance (though I'm not sure about even that case).