Hmmm... so the err "competition" does separate these. 15712 is the newer "curvy" version without a cut or C, and 2555 is the original version. I think it really comes down to if we know which variations associate to which set. If they cannot be associated back to sets with the automated LEGO import into BO, there's little point in having the variant. :-(
IIRC, they are two subtly different shapes. It was never clear if the change was to avoid playwear breakage, to improve molding production, or grasping power. The latter possibility, would suggest that having the correct variant might be important for certain sets.
I do believe there are in fact 3 mold variations for 2555.
But sticking to the 2 variations on the 1st picture: 2555 on the left had a too strong grasping power. Not easy to remove without wearing out the Boat Masts, Bars and Antennas.
LEGO eased that grasping power with the 2555 on the right, but alas, not entirely: still a tad strong.
LEGO finally nailed it with the C type clips and 15712 has the ideal grasping power.
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But sticking to the 2 variations on the 1st picture: 2555 on the left had a too strong grasping power. Not easy to remove without wearing out the Boat Masts, Bars and Antennas.
LEGO eased that grasping power with the 2555 on the right, but alas, not entirely: still a tad strong.
LEGO finally nailed it with the C type clips and 15712 has the ideal grasping power.