40 sats makes up about 2% of the current fleet - so a rounding error in cost and time. The important part of this news is how those 40 sats deorbit and leave no junk either in orbit or on earth.
An entire launch worth of satellites is not a "rounding error." The carbon impact of just one launch is pretty obscene.
It really isn't. It's what, 15 aeroplane flights' worth? For the sake of bringing internet to hundreds of thousands of people? By letting people shop online or stream entertainment they've probably paid for themselves in reduced car journeys already.