I have to say the reason I still want an iso is at least I have a much higher guarantee it will work. I just spent about 4 hours this week trying to get clonezilla to boot from usb and could not get it to work. EFi. Legacy. Everything I could think of. And this was on a reasonably modern server (2015/16 ish lenovo with a e3-1270 V5 )

Come to find out it was the fact that it was a usb 3.0 flash drive. Grabbed a 2.0 drive and everything worked fine.

Had I had a dvd burner (Ironically the computer in question did have one but it was not useable till i fixed it.) I would have saved myself significant amounts of time. (Or randomly grabbed a crappier flash drive.)