I haven't bothered responding to your comments in particular, because they were unnecessarily snide and I've learned to not dignify such posts with a response. However, I might respond to your specific question "doesn't speed concern you?" The answer is that that all depends on what one is doing and how fast one needs it done.
If I'm burning an iso snapshot to the optical disc for a new liveCD, I'm not really under under any time pressure, certainly not enough that I would need or care about an increase in speed. It's fast enough already, burning in a few minutes. (And at a lower speed that I set.) Besides, whether writing to a DVD or a USB drive for a new live medium, I want primarily not speed but accuracy. (Which is why I set the burn to a lower speed, probably minimum.) I want more than anything else to know that the live medium wasn't written with any errors; and if that took a little longer, let it. If the USB drive completed writing the liveUSB in a few seconds or something, I can tell you how I'd react: I'd suspect that the write failed and I'd better not boot the liveUSB.

I don't know what you suppose I do that I need the fastest writing I can get; but consider my equipment. For going on the last seven years, I've been using old and obsolete ThinkPads. Why? Because I can. All I do is use the web, use e-mails, and maintain my system. By a fortuitous mistake, I bought a Thinkpad T61 in fall 2013--and then my desktop computer failed. I started using the T61 as my main computer because it was all I had. It worked so well that I never went back to a desktop computer until recently. And even my new build is an experiment in using old technology, to see if I can get away with it.

I'm sorry if I caused any offence. It's clear that I didn't agree with your approach, and felt clear to tell you bluntly because of your subject title, but never meant to come across as snide. It's not my style.

I tolerate slow myself. using a raspberry pi 4, and it's ok to a point. But when you boot one of those live cds where the files are in little segments all over the shop, you get very fed up with live cds. Optical is also such an unreliable medium, particularly where slow slpped are unavailable. My 2012 dvd drive has a minimum speed of 8 and will read or write nothing reliably.

It's true I wasn't taking you that seriously, but you weren't yourself either at the start.

Acknowledged. I also acknowledge that I'm oversensitive to sarcasm and distrustful of people on online discussion forums.