You probably noticed "Run in ReHIPS DeployHelper" and "Run in ReHIPS DeployHelper as administrator" context menu items for .exe and .msi files in explorer. So what is this DeployHelper? Let's take a closer look.
As you probably know from this blogpost
https://forum.rehips.com/index.php?topic=9529.0 DeployHelper is one of the ways to install ReHIPS rules. It's meant for installers/setup-files only. For example you have a setup.exe for some program. And you want to have the program isolated. Of course you can install it the usual way and then choose to Allow in isolation during first start. But some settings may be lost, you'll have to copy it enabling Copy User Data, why the hassle. Install it straight into the isolated environment. That's where DeployHelper comes into play.
Basically it starts the setup from the isolated user, so everything is installed for that user, i.e. straight into the isolated environment. It's also possible to "Run in ReHIPS DeployHelper as administrator" in case setup requires administrative privileges, in that case the user will be temporarily added to the administrator group.
But keep in mind, DeployHelper doesn't provide protection! It's there to help you install programs only.