I assume when someone posts something on tumblr, they want it to be seen and reblogged. But I don’t think that’s your question.
It’s a paradox, that one wants to use their will to change the universe but must remove lust of results.
I think there are various ways to use sigil magick. Keeping the sigil hidden and destroying it is valid. I would use that method for internal changes.
But treating a sigil as a kind of entity of its own is valid as well. I think if you’re trying to change things externally, you may be better off planting the sigil into the minds of as many people as you can.