We all know that Luffy is pushing his body hard.
So why?
To be strong? Or to protect your friends?
If you ask me, the main source of Luffy's strength is his friends.
One of the crew members is likely to be kidnapped for Gear Fifth.
In this case the enemy must definitely be strong.
Example : (Blackbeard,Kaidou,Big Mom)
We didn't see Eiiçiro defeat Luffy in a proper battle.
So one day if you want to defeat the Yonkos definitely need to better use the fruit and the haki.
Luffy knows this very well.
One day he will definitely use the gearshift to strengthen himself and protect his friends.
