Signing a rental agreement in person - aren't email copies legal?

Hi, I am based in Canberra and trying to rent an appartment in Sydney. I am trying to manage things remotely as I have kids in Canberra. I have arranged for a rental in Sydney with my niece who has just arrived from overseas as a PHd Student to be the co-leasee . We deposited the bond/rent etc and are trying to see the appartment to arrange furniture etc , so I asked if I could get an email with the agreement, sign it, scan it and email it back and carry the original across on Saturday, however, could we get the keys to the apartment as my niece would sign off on Friday in Sydney at their office, but the agent stated "Unfortunately I cannot email the lease as it must be signed in front of a staff member and an email copy is not legal." & "Unfortunately I can not give out the keys until the lease is signed by all parties" Is this true? and do tenants really have any rights at all?