You can indeed use zone R as a silver/gold for dom check-in. Have done it frequently when the SSCI machine has refused to check me in (usually because the flight has been cancelled at the last minute )
The only drawback is that you then have to walk all the way to the other end of the terminal to go through security. However, if you're travelling with bags after this new 'enhancement' I suspect it will still be faster than queueing at the 'fast' bag drop. (I use 'fast' here in the same sense as 'enhancement' )