That's a fair point. Though not needing network access during normal use, plus not requiring a Node runtime, are already compelling reasons to me.
[...] it provides tab completion.
That's odd: it doesn't on my end. I had to set up the completions myself.
For the fish shell you can do so with:
# ~/.config/fish/completions/tldr.fish
complete -c tldr -f -a "(tldr --list)"
Ah, nice when the package maintainers do that for you! (I'm on Ubuntu LTS, so won't be holding my breath for an APT package :P)