Well I made the assumption that one of the most valuable items in Skypeia is the dials. Bellamy did go to Skypeia and he did return with a golden pillar(surely weighing over a tonne) so why not a simple, light and easy to hide a dial. With that said, Bellamy's ability would make the use of a impact or reject dial quite potent.

Sure, his 195 m beri bounty implies that he should be a tough opponent, but when in a clinch, those dials would come in quite handy for him, and lets face it in the New World, i'm sure 195m beri aint nothing special. So he's bound to be fighting tough opponents, making the dials a nice trump card.

What has peaked my interest more is the idea of storing one or more of the Kings punches in a dial. If the punch is as insane as its hyped to be, then the ability to store that power for a future fight could be a factor. Quite possibly, Bellamy collects the punches power and turns it over to Doflamingo.

Seeing as to the sticky position Doflamingo is in with Kaido and the SH/Heart pirates, it would be an ace in the hole.