For us it would be that these two things, dagster and FaaS, are similar and complimentary. Dagster can provide the “how things connect” and orchestration for the data flow while the functions are the units of work. I don’t think it’s hard to create a template for a function that could be based on your code (a Docker file and a startup python script, see
https://github.com/openfaas/templates/tree/master/template/python3) and tie the two together.