Can't mind read the guy obviously, but the usual motivation that I'm aware of is that you pretty much fuck over everyone else that comes later. Upscalers improve over time, but in terms of distribution, recency bias is strong and visual treats are inviting. So when those much better upscalers eventually come around, what's more likely to still be available is the secondary source you distributed, which is already upscaled once with a then-inferior upscaler. This leads to a form of generational rot.
Other likely explanations are:
- them not liking how these upscalers look: you can imagine if they can nitpick minor differences between different encodes that most people don't notice, they'll hate the glaring artifacts these filters usually produce
The reasons stated against upscaling were that (re-)encoding video files should generally be done in a way that preserves as much of the original information and intent as possible. AI upscalers add information where there is none, thus modifying the video in a way that goes against that goal.
OP makes zero comments about content generation, and the complaint is about upscaling introducing artifacts not in the original source. No different than hating a bad 4k remaster / sharpening.
That advice is not universal, and without context it's simply wrong.
You wouldn't upscale a classic film in this way, but there are plenty of low-resolution shots that benefit. Especially with VGA resolution renders and modern AI workflows.
Just looking at the Topaz marketing, you can see a lot of places where it indeed does work. And 20-year industry professionals are using it today for their day jobs.
If you want to say "don't upscale a classic film in Topaz", say that. Because context makes the advice correct. This blanket "do not use" statement is flat out wrong.
Why? I only know Topaz and I always thought it had its narrow but legitimate uses cases for upscaling and equalizing quality?