Reddit mentions of Car 08-13 Auxiliary Aux Port Stereo Adaptor for Toyota Corolla Tundra Tacoma RAV4 Highlander Jack Adapter Input 86190-02010

That's a good use, because that is exactly what a power strip is designed for, and, as you point out, when there is a a spare outlet - but that isn't what the LPT is claiming here.

They're claiming that somehow it would 'guarantee' finding an outlet abroad, and that you can share with other travellers. But that would only work if those other travellers conveniently happen to be from your own country, or happen to have those adapters on them.

Imagine you're from the USA, with a type B USA power strip. You're at Frankfurt airport and all the type F outlets are taken. Unless you can find someone else charging a US device, people aren't going to be that happy for you to take out their type F device and then offer them 5 type B ones they can't use!

Power strips can be super useful when travelling abroad, but more often for applications like yours than this LPT.

I carry a universal adapter with 2 USB outlets and a universal outlet. I can either find someone charging a USB device that I can then share one of my USB outlets with (and charge 1 usb and 1 AC of mine), or I can 'pass through' their plug (of any type) and charge 2 of my USB devices. It actually meets the requirements of this LPT way better than the LPT itself.

I think its an essential, certainly is for me. I have this one:

https://www.amazon.co.uk/gp/product/B01J18QF6E/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Which I would recommend, hasn't let me down yet. According to manufacturer good for over 150 countries.

I recommend this

Two USB charging ports and you can charge your laptop or whatever at the same time. Even comes with a spare fuse.

I have been using mine for 6 months and it gets a lot of use. It has been excellent.