TBH overseas Pakistani's can do a lot more for Pakistan from outside Pakistan than within in terms of remmitances, attracting FDI's, setting up businesses, education exchange opportunities, promoting a soft image of the country e.t.c. The PM also made a very good point that by enabling overseas Pakistani's to vote, current and future governments will have a stronger incentive to take steps to make things easier for overseas Pakistani's otherwise risk facing a voter back clash.
Just because PTI has had to impose much needed necessary Austerity measures and tough economic decisions where there hands are tied because of 99% of the population not filing and paying their taxes does not mean that you have to make a one time exception to aleniate their vote bank. If the people of Pakistan want change, they are going to have to make sacrifices as well and not put everything on the government and force them to take additional loans that they cannot afford to repay.
Also not every overseas Pakistani is living in comfort as well, they have to work equally hard if not more than a well settled local vs local Pakistani's for their living.