Leaving a post open because you might need it later sounds harmless, but it usually leaves the whole platform one tap away.
A saved post list changes the default. Instead of depending on the feed to surface something again, you keep the specific thing you cared about.
A list has an end
Feeds are built to continue. A list is built to be checked. That difference matters when you are trying to use social media without letting it use the rest of your attention.
Keep only what earns its place
Saving is most helpful when it stays selective. Keep the post, recipe, video, or thread you actually plan to revisit. Let everything else disappear.