Sanaya natuarally has grace, flexible body, love for dance and the ability to back it too. She hasn't simply had formal training till now.., So these are all big plus points.
She looks fragile and beautiful - a big card for audience votes.. cz her performances with her partner look very beautiful from purely a visual POV also.
And she is immensely popular as u have mentioned. So if she manages her own 50% of doing her dances well and showing reasonable improvement (which I am sure she will cz her week one and week two performances were miles different! She improved so much) there is no way her fans wouldn't ensure she gets the best votes from them..
Hell even if she didn't dance that well we would vote, and the 'we' in this case is an absolutely huge number of people across the world and across time zones who have come together to vote for her..
Like for an example, except for VD I am sure voting SMS/online ends for most contestants by 9 am IST.. But for VD & Sanaya its just the start of our other time zones like UK/USA etc..
So she is putting a great effort and with the fans backing she sure has a very good shot at it!