Must have had a theoretical demand once, but it closed during the first world war because there was no demand, and it was closed formally in 1927. If it was still there they'd probably be closing it anyway because a flat junction would get in the way of the through service.
As I understand, this curve was used more for meat trains to Smithfield than for passenger services. There was probably a coal siding somewhere down there as well, but I'm not so sure about that. Freight running underneath London may seem bizarre now, but there was quite a lot of it going through Snow Hill, and I understand through the ELL as well.