It's also important as most long range airliners take off with more fuel than they can safely land with. The air frames are very heavily optimized as every pou

It's also important as most long range airliners take off with more fuel than they can safely land with. The air frames are very heavily optimized as every pound matters. If you always landed with the same weight you took off with, you'd end up needing to make the landing gear and surrounding structure significantly stronger to prevent excessive wear over time.