There is a lot to be gained even if each and every projectile is shot down. It is a war of attrition.
A $2M missile vs. a $2,000 drone: Pentagon worried over cost of Houthi attacks
“That quickly becomes a problem because the most benefit … is in their favor,” one expert said.
https://www.politico.com/news/2023/12/19/missile-drone-pentagon-houthi-attacks-iran-00132480
I don’t see how that helps anyone. They both lose; just at different rates.
Would you say the same for Ukrainians fighting Russian forces on their land?
No, because driving a ship somewhere to protect a trading route or build a port is not an invasion. The ships will go away, once the mission is over, but russia wants to stay forever in Ukraine and make it part of russia.