I agree with Master of Haki. I once made a theory about Bellamy, I think it will be important when Luffy starts to take his own turfs, like Wano will probably become Luffys turf after this arc. And seeing Bellamy visitting those places and putting down proper Strawhat Flags makes sense.
Luffy made himself a great friend just by fighting him and showing him how fighting and motivation can safe someones life. The opposite of what Doflamingo did because Doflamingo was sacrificing lifes literally for his own sake.
What Bellamy will do is spread the true meaning of the Strawhat around the world and we all know who will become the hero of the world EoS. It will be Luffy, so having flags to honor the hero of the world sounds Cok Gรผzel.