in your announcement page, the visuals states 100 gpus but it is also stated that they are 1060 and 470...1080 ti are a lot more powerful than 1060s..maybe you have different minimum requirements for different graphic cards?
Actually with one single GPU it can't be of much. Minimum GPU number requirement is needed to provide fast rendering and good customer experience. Indeed there is difference, 1080 is generally 20-30% faster than 1070. 1080 ti is an expensive card but I prefer to manage the minimum number of rigs possible.