I know people who are laptop power users who are fine traveling with just a tablet and an external keyboard. (They still use a laptop when they're not traveling.)

Good for them but I've never been able to make it work for me. I'll just carry the extra weight. But, to your point, it's also true that, beyond getting an external keyboard, I've never really committed to making a tablet work for me as my only travel device (other than a phone).