It's not just about the 250SP delegation, but also the support of your work.

The peculiarity of the voting power (100% or other%) affects the charge consumption of your "battery". For example, 1 vote for 100% or 2 votes for 50%
Right now, as long as your SP is not large, it doesn't really matter. The income from your vote to both the author and you (as a curator) is small. But as your strength grows, it will make a big difference to everyone.