I'd say that any bonus you get to attacking would quickly get offset by your penalties.

It would hard to be as effective if even you don't know where the end of your weapon is. You might have some bonus, but it would be awful inconvienent.

Getting disarmed would ruin your day.

You wouldn't get much bonus on feint. THey wouldn't know you are feinting.

As for catching the returning dagger... heck no!