CD vs. Installer program

I got into a rather animated discussion about what method to use burning an .iso onto a flashdrive. Personally, I D/l the .iso and use a program such as Rufus-Unetbootin-LiLi-or any of many other .iso/bootable flashdrive programs. An opposing and very adamant view stated I MUST get the .iso, burn it to a CD/DVD, then use the CD/DVD to burn it to the flashdrive. So, what method do you use and why? In responding, please give good, solid reasonable answers and, if possible, "links" to validate your viewpoint.

Thank You;

:hattip:Rick