I've seen them used less for privacy and more for getting around permissions/limitations on controlled systems like work laptops. (That's assuming work devices haven't locked down or disabled USB drives.)

More often than not, there will still be some artifacts left over, whether it's recently access files or terminal history that indicates a portable device/app was used.

If you're looking at USB things specifically designed for privacy, something like Tails is where it's at.

I've only seen it used to play games on school / public computers. The game runs from the USB, since the user doesn't have permission to install software on the computer's harddrive.

Installation restriction at work. You may have rights to execute .exe but not to install app.

I also have a dozen of utility app I daily use (image viewer, PDF viewer, process killer, inkscape, gimp, etc...). I just have to zip my progs folder to backup and I won't need to reinstall everything if my computer die (which happened last month BTW).

Use software that you are not allowed to install mostly.

Privacy benefits would vary with different apps - you'd need to really dig into that.

Any purported benefits might stop mum from checking your browsing history but wouldn't stop a determined attacker, although they would likely need to have things in place to monitor you before you showed up with your USB drive.

I can't really think of what the practical benefits actually might be?

It might feel private, and it might even feel convenient in some cases, but as a general practice it seems like a whole lot of horsing around for very little benefit.

Not having to set everything up again wen inevitably hafta reinstall Windows from 0 again

… that is if portable app's actually portable , if your """portable""" app's just the .exe but everything still stored in «USER FOLDER»/AppData/.\* I'm stealing something from your house ‼️

I used them on Windows to manage a handful of websites. I'd have a Websites folder with sub folders for each site, and a few portable apps in each one. I'd have Thunderbird and Firefox at least, and they'd keep everything separate.

For me at least, it made things a lot easier than trying to remember to log in to profiles etc individually :)

I have a utils die full of portable apps. They are just things I use occasionally that I don't want to actually install, like a cd writer, sysinternals, benchmarking apps, mkv tools, and more.