In real life engineering, an approximation of a problem is often good enough to find a solution than needing to be totally accurate, as long as it is over-engineered to be within tolerance. For instance, if I need a shelf to hold 48.72 kg, I may as well round up to 50 kg and make the math easier.

Same with the gravitational constant or pi, why not just use 10, or 4? As long as you’ve rounded in the correct direction, and you’re within tolerance, you can make the calculations far easier by assuming away the unnecessary details. If force of drag from wind resistance is within my assumed tolerances, I can just not bother with the calculation, knowing that I have enough overhead.

It’s not the most optimal or cost efficient way of doing things, but it’s often faster and easier.