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Because the voting power you might have on other platforms may not be favourable enough for voting at that moment, which includes hive itself. I hope you can understand my point now.

But your voting power is only one, and it is the one related to the hive blockchain, no matter which viewer (leo, ecency, peakd, hive.blog, etc.) you are using to see that information.

Thinking a bit, perhaps the option is to have the possibility to "make invisible" the voting power of a user. It would be necessary to think about the advantages and disadvantages of that option.
But as far as I know, it is not possible to hide that information at this time.

Because the voting power you might have on other platforms may not be favourable enough for voting at that moment, which includes hive itself. I hope you can understand my point now.