well many reasons
1. trainer capable
2. their positive experience with SU30 2 seater
3. 5th gen is so integrated target wise that the on board computer is your "co-pilot"but india i think still wants it to be the old school way
PAKFA yes 130-140 fighters before 2022
FGFA -india is going to be doing way more work on it so it depends on the HAL's facilities
all in all deal is done, contract signed