Yes, it's a requirement. You cannot create an MDE if the application doesn't
compile.

Yes, you have to ensure you code is error free.

On the other hand, think about this:

   Do you really want to try and deploy and run a application with so many
errors? What happens if your sales report is broken, and the company uses
the results of that report to spend millions of dollars of advertising based
on that sales report, and it is wrong?

You really do want find out why the code is broken, and why so many errors
exist in your application?

I would NEVER run an application with many errors in a production
environment.

In fact, even in the rare cases where I don't use a mde, I still go
debug->compile virtually after EVERY time I add/change code to an
application. If you don't that comple each time, then you could add new
things for a very long period of time, and THEN discover you have a problem.
It is better to fix things AS you add them...not some time down in the
future.

You don't want to delete that code that fails to compile....you want to fix
it so it compiles free of errors....