Recharge with Rs99 PRIME offer anyway. Till now they are using mostly RCom towers with least rent. After commercial launch they are going to switch ON the other company towers incl that of "Bharti Infratel". Hence the coverage may improve after April.
Even if the coverage was NOT improved (and you have done PRIME recharge), there are 2 options available for you.
[1] Use the Jio SIM in JioFi2 near the window, where you are getting better signal and continue enjoying Data for dirt cheap.
[2] Just forget the Rs99 and think it as charge for using Jio services till March end, so that you may NOT have guilt of using some services for FREE. This option is still better than NOT doing Prime recharge and regret later once the coverage was improved.