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It's not just profitability but also management. There are other reasons including:

  • if we lower too much, it's opening door to abusers who create multiple accounts. We manually upvote for quality control so this would also create too much work.
  • if someone delegates 1 SP, they should receive 10 SP upvotes which is virtually impossible to do with our current Steem Power. It's not even 1% vote weight... 25 SP is the minimum we can do.

Thanks, very detailed explanation