After running my WordPress and Blogger blogs side by side for two months now, it's become clearer how to make the two blogs work more efficiently.
WordPress works better for longer posts where the more advanced features on things like formatting and image galleries comes in handy. Because the home feed is just displaying the featured image and the few first lines of text, it works well for displaying a library of full length blog posts.
What WordPress is not so good for is short posts with just one or two images or one line of text. It rapidly becomes cluttered, and because you need to click on each post to actually view it, it just doesn't work for looking at dozens of short posts (AKA. "shitposts" or "tweets")
Two main drawbacks of Blogger are that all these short posts go pretty much unseen in search engines so it's unlikely many people will ever see them, and because Blogger is owned by Google there is always the risk that they will one day blacklist the blog or even delete it altogether.
So my plan is to keep using my WordPress blog www.frot.co.nz for full length posts but post my short random posts on Blogger.