It means that they have allotment letter, as well as possession letter, i.e. plot is ready for construction, and all necessary utilities / facilities (like road, electricity, sewerage system, water supply lines, etc.) have been successfully provided.
Despite all this, no doubt, aapko ghar sey koi nai nikalay ga, but that plot, etc. will always remain property of Bahria Town.
Aap owner ho k b owner nai hotay!
Secondly, no bank gives loan for Bahria Town; be it for house construction, purchase of property in it, etc.
Only Escorts Bank ( https://escortsbank.net/ ) gives loan, but again, it is, sort of, Bahria Town subsidiary, and interest rates are very high.
Since no bank gave loan to Bahria Town, that bank's purpose was to give loans for construction, but at high interest rates.