- As soon as you have more than 5 boxes, you need different tools for your everyday tasks, interactive SSH sessions just don't work. But you know that already.
- So you've found yourself SSH'ing into a particular box, because that's just the best way to work on a problem. Either it's a pet box (in which case it makes total sense to drop your dotfiles there), or it's a cattle box and you don't care about the trash you left behind, because autoscaling will clean it up for you.
It's actually not that difficult to maintain context if you use completely different shells (with different-looking prompts) on your own machine vs the fleet. It's like code-switching when you talk to your friends at the bar vs co-workers.
OTOH, I’m also against, for example, installing zsh fleetwide in production fleets to accommodate choosy folks. So I’m on both ends of the problem, and know it.