Installing an iso from a usb drive and installing an iso after mounting it as a virtual drive seem like they involve roughly the same level of technical skill to me. Booting from cd or usb was a routine school or business activity for decades. Mounting an iso as a drive has been built into Windows for a much shorter period of time. The last time I used Windows, you needed third party software for that. I would bet on a random person off the street to be able to do the first one more reliably than the second. But, more installation options are always better.