Jumping on here. What do we mean by “simple”? 
I’m using Quantum (shared by @Sebb above) for a process that I need to fire off every 24 hours. I don’t care if it has a response or not, and I gave the process a ripcord to alert me if it fails catastrophically. I initially began building a genserver for my task before I realized I was over-engineering for this particular case. Implementing Quantum took me slightly longer than it takes to type mix deps.get and hit return. Simple.
If I needed to maintain state or recover a user session in a meaningful way, I would definitely go with a “simple” GenServer implementation. But this entails more code to maintain and test. On the other hand, a GenServer may be more flexible in the long run if my organization adds more requirements to the task.
For me, the most important consideration for this kind of “how long is a piece of string” question is always: what’s the right tool for the job?
How much time do you have to implement it? Is the job this task performs actually important? Can you commit to maintaining it? Do I need crash protection? Will the application fail if this piece isn’t running reliably? Or is this job a nice-to-have bit that’s not going to inconvenience anyone if it doesn’t run every day?
Simple in one regard probably means tradeoffs in another, right?
