GG is the only agency that has successfully executed and sustained over time an incall operation on top of an outcall operation. The other outcall agencies that tried it, not just Eleganza and WT, but other agencies as well, all experienced the same problems UB mentioned. Some also tried hotel rooms, rather than renting out condos, the better, safer and more discreet alternative.
The question is not whether there is a need for it. There obviously is. The question is whether any agency can successfully execute the operation. GG found a good location and appropriate condos and they have the ideal, model incall operation IMHO.
It is high risk, high reward, like the flea flicker play in football. When properly executed the flea flicker can result in touchdowns. When poorly executed, it results in enormous losses and 4th down and 30 situations.