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Tha would perhaps speed up the internal market, day trading and such. But would draw people from the SP position, that might make Steem bit more unstable.

Rising the interest on SBD too high would create an incentive to stock value there instead of STEEM and SP. Which could have a negative impact on the system. My understanding is that the Witnesses is determining when these interest rates are to be changed. So, it’s a tool that can be used to stimulate the internal market when we see fit.

I say we, since, we all can vote or the Witnesses we wish to represent us.

Thanks for you comment and upvote @ender!