Look at the Tsiolkovsky rocket equation—a rocket’s delta-v (velocity change potential) is proportional to the log of its mass ratio (its mass with fuel divided by its mass without fuel). For modern rockets, that means about twenty kilos of fuel for every kilo of anything else (the rocket included). You really don’t want to add structural mass if there’s any way to avoid it.
Look at the Tsiolkovsky rocket equation—a rocket’s delta-v (velocity change potential) is proportional to the log of its mass ratio (its mass with fuel divided by its mass without fuel). For modern rockets, that means about twenty kilos of fuel for every kilo of anything else (the rocket included). You really don’t want to add structural mass if there’s any way to avoid it.