Why have a turn and bank?

Pray tell me sir Super User, how I can slip my non-rudder pedaled Coupe? Other than temporarily turning opposite the wind?

That is what I did, took out 16 lbs of vac instruments and hoses. I also installed the outside air temp probe and the AVlink for the AV-30, so I get ADSB traffic on the AV-30.

I have one but don’t totally trust it. Don’t have an attitude indicator either, compass is fair butI hope to eventually dump both and the Venturi tube and lose some weight and install a UAVIONICS AV-30, get 13 pieces of useful info in one empty hole in instrument panel.

uavionix.com/products/av-30/

Look into getting a Dynon Pocket Panel. It is a portable, GPS derived AHRS. Both I and my friend have 415-C Ercoupes use them and find them very helpful. 

I was just about to post regarding flying without an attitude indicator. I also do not have a bank indicator but I do have a coordinator ball which is essentially just a level.

My question is, how does someone like me with only 6 hrs of training know when my steep turn is past 60 degrees without an indicator?? I just purchased the ercoupe and will be switching over to it after renting 172s. Should I add an attitude indicator/and or turn bank indicator as a new pilot? Or is there a trick to knowing when the turn is too steep?

Ah a turn and bank in an Ercoupe.
I personally like it for a number of reasons.
There are times when a standard rate turn is required like at night or with fog. Or doing holding or procedure turns.
You also can check your rigging to make sure your turns are coordinated. Same for flying straight
Plus it is a light weight way to fill a hole in the panel.