Is there a point of doing a mission chain when it first comes out (as a weekley mission )
as after the weekley missions they beome normal missions so you can get all the moduels and buildings after the weekley mission ,

so is there a point in doing the weekley missions

yes you get them before everyone else plus as soon as its archived you can change to the race(if there is a new race).

Some missions are harder than others to complete, so it is possible to do the weekly missions (to get the good modules and buildings) even if you didn't finish the missions before.