WinToHDD Professional 4.4 is a simple utility *that I grab* when it's on GOTD for the *potential* capability to create a bootable USB stick or drive to install more than one OS, e.g. both 32-bit & 64-bit versions of Win10. I have not used it to do that -- why I say "potential" -- because I really haven't had the need. But I can easily spare the 34 MB on a just-in-case basis, so I grab it while it's free.
Now the app itself is portable until you activate it -- at that time a key & logs are generated based at least in part on the hardware ID, with one entry added to the registry, HKLM\ Software\ Hasleo\. Note that there are 32-bit & 64-bit versions.
What it does...
Actually I'd make the case that for creating a bootable Windows setup USB stick/drive, rufus is better, so don't bother with WinToHDD Pro. For cloning a Win10 installation, to move to a different hard disk on the current or a different device, I suggest Macrium Reflect [free or paid] -- since cloning ONLY works if both drives are connected to the same device, restoring an image backup stored on a USB stick/drive works just as well if you want/need the added flexibility.
For rescue capabilities, if Windows runs, run setup from the ISO. If Windows doesn't start, 1st isolate the problem -- is Windows broken or the boot files [BCD]? Either way the preferred, easiest solution is to restore an image backup of the boot partition &/or the Windows partition. Failing that, if the BCD is the problem, create a WinPE bootable USB stick, boot to that, and use EasyBCD or try the more difficult Microsoft tools, BCDEdit &/or BCDBoot [/? for help]. The paid versions of Paragon HDM & Macrium Reflect also let you create a USB stick with BCD repair capabilities. RE: Win10 itself, Win10 normally adds a recovery partition [sometimes more than one(!)] or with Win10 2004/20H1 you can download the same content [assuming your network adapter works without Win10 running] from the boot menu, and *try* to fix things using the recovery options. It does not always work well, or at all, but if you don't have a current image backup, it might be worth a shot.