I agree with you. Though I am using Jio 4G now but I am actually interested in Jio FTTH in the long run. It is not feasible to provide unlimited plans (or FUP plans) on 4G once it is commercially launched. The employee at the store yesterday said that the 4G prices would be near 3G prices of existing networks. So, it cannot be used for regular use for whole month.
But in case of FTTH, a decent FUP or unlimited (both are fine for me) is possible at decent prices as most ISPs in India are already doing it. Even if they can provide decent plans like Beam Fiber/ACT Fibernet provides in Hyderabad throughout India with good customer service, their FTTH would sweep off almost all BSNL customers (as well as other ISP customers) all over India almost instantly.
The Jio employees in the store said that the Fiber plans (which I suppose they meant FTTH) would also be launched soon. Hope they launch it at the earliest. Eagerly awaiting for the same.