They work very well for "worker" processes. The default ssh package on Debian uses systemd template units for the user process; I've used them extensively for job queue workers, in combination with max execution time and a separate timed job to monitor queue load (essentially automatic scale up/down of queue workers).

Realistically if your prod environment relies on you manually running `pm2... ` or whatever, you're doing something wrong. User Experience should have about 0% impact on how your service daemons run.