> if what you're vending is the software instead of the service (not what people usually do now, but there was a time)

I'm very curious what this means. Can you give an example?

Giving the client the executable to run, not running it for them. This means you can't hide the artifact from the client; for an interpreted language, this means recovery of the source code would be much easier than with a compiled output.

That being said, it's still possible to reverse engineer the code; it just makes it harder.

You could also run a limited demo of your desktop application in a browser, where people have to pay to get access to the full thing.