You havent watched the video then, wherein Dave does a short review of the product and provides his positive opinions of it (conveniently coming across the major new feature of the product). Its all mucky and a clear advertisement/personal endorsement without disclosure and the repeated distancing from the real source of the product.
I think it's fair to say that there is some mutual benefit in these kinds of previews/reviews etc., for Dave and Keysight in this case: Dave gets something to talk about in his videos, and for us to talk about in the forum, attracting viewers and readers if it is good stuff. Keysight gets some publicity for their scopes -- some good, some bad, but they certainly get attention. Look how busy the "New Keysight scope" thread was throughout all of February, based on very little content...
Nothing untowards in this, in my view: Dave is very clear and above-board about the rules for submitting any new equipment for review. He clearly reserves the right to critique the product, nitpick, rant etc.:
https://www.eevblog.com/reviews/. There is no money changing hands. It is an exchange of "advance information for publicity" from the manufacturer's point of view, and "talking about products -- good or bad, as long as it is entertaining and attracts an audience" from Dave's point of view.
And it is not some private conspiracy between Dave and the big scope manufacturers either. Every little startup or semi-professional hobbyist submitting their stuff to Dave's mailbag essentially becomes part of the same symbiosis. No need for conspiracy theories here, as far as I am concerned. I think we can assume a grown-up audience which can put this in the right context.