For me tumblr does best in that you have chains of responses (reblogs) in images/gifs and text form, that then are reposted on one's own blog for their own followers to experience broadly in a singular dashboard whose ordering isn't really manipulated (like twitter and instagram are, to my extreme vexation).
Also, because tumblr makes it easy to create side-blogs, you can follow a favorite person for their specific stuff. For example, if my artist friend has an "inspiration" blog I can follow that blog instead of their "personal/vent" blog. Similarly if I'm looking for some kind of tea-specific blog I can follow a stranger's side blog without needing to also be exposed to the stranger ranting about a political opinion I am uncomfortable with.
Furthermore, it's one of the large social media sites for which there is a significant and semi-permanent resource and groupings for a variety of LGBTQ/diversity/political/fandom interests in a way that is more flexible than a subreddit or an interest forum. You can follow the individual blogs that you're interested in instead of needing to follow a whole community. So if you don't want to be exposed to some aspect of a community it's relatively trivial to just not follow the people involved.
Twitter has a lot of this, but the lack of easy threading posts and out-of-order feed really ruin it for me. Several of my favorite artists left tumblr for twitter and I've had very little success following them from there.