The best practice, quite simply, would be a hierarchical system
The top nav is your top level navigation, the side nav is the sub navigation
It suits systems where the top level items are fairly independent of one another, but the second level items are more related and, more importantly, are clearly "children" of the top level item
Eg at the top I click settings, and on the left are a variety of categories or types of settings.
If you don't have a clear 2 level hierarchy, this type of navigation can be confusing: the user should intuitively know which top level item they need for any second level item. If they don't, you're using the wrong navigation system
A bad example of a similar system, I always find, is the PHPbb forum system - even as a long time user, I can never remember whether some settings are in "Profile", or "Preferences"... Because the delineation between the two wasn't good enough.
AirBnB is quite a good example: look at your screenshot, and you can see that all the items clearly belong in the same tab, and you'd definitely know where to go to look for them. It's intuitive, and navigation should always, always be intuitive. It's common almost everywhere, though: Twitch uses a similar system, but so do most sites nowadays, at least for their "settings" pages
As to your specific question about having only a couple of items on the left.... No, that's not a bad thing, although you may want to consider dropping the second level entirely for just that page, if the two items can sensibly be combined
