I gave it a try on my HTC one SV phone, but it doesn’t appear to work, so I suspect my phone is one of the HTC models with a write-protected system partition.
When the APK is installed, Google gives a warning that this app attempts to bypass Android’s security and advises not to proceed, so I continue anyway. When the App launches, it displays a button to perform the operation. Once touched, it displays a message saying the phone will be rooted once it reboots. However, when I tried Apps2ROM (which requires root) and attempted moving an app, it told me that I need root access, where as this works fine on my other rooted phone.
I’m not sure if unlocking the HTC bootloader removes the write protection, but will give that a try later. The catch with unlocking the bootloader is that it wipes the phone.