Is automating repetitive, menial tasks beneficial? Hell yes, if it's shit you don't want to do repetitively. The monetary value is equal to how much life it gives in return for something you don't want to do.
Is randomly buying consumer "smart devices" worth it? No. That's way too general a question and most are just network security holes or short-lived, proprietary ewaste.
Yup, electricity isn't terrible on these. My htpc/nas/util server has been my basis for everything for almost 20 years now. No reason not to