That’s more or less what I use it for — keeping sessions alive. I don’t use 90% of the features. vim does splits, and there’s ctrl-Z to background it and get a shell.

I know I could get more out of tmux but haven’t really needed to. I use it with the default config. I have learned from experience that the less I try to customize my environment the less non-billable time I waste trying to get that working and maintaining it.