I believe it is still quite common for private operators. It is also used as one of the codecs for GSM and iDen voice. I have heard of hams experimenting with using gsm-based equipment modified for ham bands Also, it was used in DAMPS, which was phased out, but I don't know if there's a possibility of coming across some kind of unusual or private implimentation of that standard. Standard VSLEP transmissions have also been used by hams. It was used in some propriotary cordless phones, baby monitors etc.
I do agree that it would be great to have it added. It would be especially useful if there were general support for the codec in different variations, not just the Motorolla II flavor of it.
just having the option for the VSELP codec as a way of decoding any signals one might come across that use VSELP encoding. I mean, assuming it would not be too much work to add support for the codec. I believe there is already plenty of open source and avaliable VSELP code out there.