I burned and tried different distros and all of them the DVD reader laser was moving back and forth like mad and loading and install was so slow that it impossible to continue. Tried 2 different readers.
Fedora Silverblue: the optic reel was moving like mad and loading was so slow that it triggered the anaconda text installer
It stayed there for hours so I desisted
Elementary OS 8: Same as Fedora Silverblue but at least could load the wallpaper installer UI. Not possible to load live OS
Lakka OS: Lakka state on their site DVD's can' t be used anymore for their images https://www.lakka.tv/get/linux/generic/
Yeah I know USB thumb drives are like £5 but I wanted to have my silly little fun with my discs and newly bought burner. I remember when I started using linux distros didn't had this kind of problem and live versions could be used, slow but usable.
Hardware issue?
I cannot speak for “all distros” but I know from experience that this statement is not true. There are also numerous “retro” YouTube channels where you can watch people burn DVDs to install Linux on older hardware. I have seen at least one of those in the past month.
Finally, the ISO file format is the native format of optical media like DVD. When you use an ISO to create a USB stick, you are starting with a DVD image (typically). If it is a valid ISO, you can burn it to a DVD and go.
In terms of “slow”, is it possible that expectations have simply changed and we have forgotten how slow things were back in the day. DVD throughput that is working fine is going to feel slow to us today. Just like we are no longer super impressed that we can store 4.7 GB on a disc.