Yeah, for something where the performance is actually a selling point, you should probably feel obliged to include a clock or some other reference in the image. (I'm not claiming anything about this particular video - just that you really want to eliminate the perception of impropriety here.) This was a big problem in robotics for years - it eventually became standard to still do sped up videos but be disciplined about including labels, and robots finally got to plausible speeds at actual tasks - but it didn't take much early-on fakery to get people to assume that most videos were sped up.
(There's a lot of staging and other "creative presentation" that's legitimate marketing - but if you're talking about speed/responsiveness at all, you really need to be explicit.)
I think context matters; that specific video is meant to show a summary of the functionality; it's in a section called "ereader on steroids" and it doesn't say anything about speed. And there are a lot of other videos on the same page which are not sped up. https://daylightco.gorgias.help/en-US#article-493382
Labelling the speed would be nice, but I don't detect any bad intentions here.
(There's a lot of staging and other "creative presentation" that's legitimate marketing - but if you're talking about speed/responsiveness at all, you really need to be explicit.)