Why have a turn and bank?

For my flying, the Turn and Bank was useless. When it died I removed it
and the venturi which was now also useless. Replaced the Turn and Bank
with a four probe cylinder head temperature monitor. Much more useful to me
and the plane looks cleaner with the venturi gone. 

a turn rate indicator is a valid backup for an attitude indicator".

The turn rate indicator can tell you which direction you are banked, and can give you a clue as to how steeply you are banked. Flying with the turn rate indicator as the only available gyroscopic instrument is called "partial panel" flying, this can save your life if you happen to fly into a cloud

I was showing my 415-C to a friend.  He sat down inside the cockpit, looked around, and asked where the rudder pedals were.  After I explained the inter-locked system, he looked at the panel and asked why I had a turn and bank indicator since if your turn isn't coordinated, there isn't anything one can do to correct the situation without pedals.  All I could answer was, "It came with the airplane."  So, my question is, what is their use?  I've asked instructors, A&Ps, IAs, and other pilots.  Nobody has a good answer.