As someone who has experimented with open-source serverless/Function-as-a-service before (like OpenFaaS and knative), I would say that serverless sucks if you w

As someone who has experimented with open-source serverless/Function-as-a-service before (like OpenFaaS and knative), I would say that serverless sucks if you want to use it for interactive, burst-period and time-of-day-sensitive stuff. You better treat each function to run dedicated stuff for one specific thing, so do one thing and do its best, and you need to make sure that it is idempotent and not fatal to repeat -- trivial things like sending e-mails, making snapshots off a website using Selenium/Puppeteer, image/video conversion, all fall into this category. At that Eureka moment I realized why AWS called it Lambda.