Just created my first pseudo rollup summary using child relationships based on this tutorial (Page Not Found — Skuid v15.1.6 Documentation). In my case it was to create a summary of benefits and their amounts rolled up onto a parent insurance policy. I’m used to having to do that sort of thing with Apex triggers, and that has some benefits. But this method is so simple and adds the huge benefit of being able to adjust the formatting in the template without having to mass update records (because it calculates at runtime). Love it.