If Pixelfed actually siloed itself into its own network it would make a lot of sense. As is, it's chock full of pictures and text from Mastodon and other federated platforms that are not remotely artistic in nature.
The whole idea of IG, in it's infancy, before being taken blatantly and completely off the rails by Meta, was to have photographers and artists and beautiful content.
On top of that, it's just a copy-paste of IG, including all the dumb shit.
And on top of all of that, it lacks any of the copyright and AI protections that Cara is squarely aimed at.