So it's basically completely different from the seal Tsunade possesses. Would make since considering her seal actually boosted her powers to an insane degree. I guess it's safe to say that whatever she gains from here on out will be different from Tsunade?
Also, I don't think Tsunade was incapable of learning this considering Shizune would of likely noted it. She only said she was incapable.
I think Tsunade made have taught Sakura this technique because of the increase in power, and it doesn't have the drawbacks of the actual Byakugou jutsu. I think whatever she learns afterwards will be something that doesn't have the same terrible drawbacks as Tsunade's Creation Rebirth and Byakugou, but that's just my take on it.
I wonder though.. Why did she make a reference to Tsunade's seal if their seals are different anyway. Her seal is stronger regardless of it she had to worry about her appearance or not.
Sakura wasn't making a reference to Tsunade' seal. Sakura was referencing to Tsunade's monstrous strength.
Hashirama: What a monstrous strength!! That is probably more than Tsunade
Sakura: The amount I don't need to keep my youth!
Sakura was replying to Hashirama that her monstrous strength is stronger than Tsunade because unlike Tsunade, she doesn't use chakra to keep her youth. Therefore she can punch with full power.