Does the ability of "simulating" the craft before launch is really needed?

[goldenpeach]

Like the tittle say,this thread is to debate wether or not we should be able to make a simulation of a design without launching it.

There would a lot of advantages of being able to make the simulation,especially in career mode:

-Be sure that the rocket will work(no money is being wasted in rocket crashes).

-Be sure that the rocket have enough fuel to do what it is designed to do

There are other advantages,but this is the "main" ones.

BUT,there is one big disadvantage,that make me wonder if a simulation system should be implanted:cost of designing.

If we were being able to simulate a design,the cost of designing a new rocket would be really low while in real life,designing a rocket and testing it cost a lot.

Also,if we can't do the simulation,each time we would have to complete a new goal(like making a space station),we would have to wonder what's the cheapest:taking an old rocket and doing multiple launch or creating a whole new design that could achieve the goal in one launch.

Thank you for reading!