I think it's the same thing as the whole 4k bluray debacle. People seem to want the feature but in reality, how many 4k bluray movies are being played on the console?
It's 'nice to have' but then if nobody uses the bloody thing, what's the point.
I think there is some long-term utility from a historical or archival sense, although that's a vanishingly small consideration save for future historians of tech.
Truly compatible platforms can leverage tools and software bases longer or reduce the shock of generational transitions, so there is utility from a non-user standpoint.
As to consumers, I think the utility is along the lines of avoiding a death by a thousand cuts, or helping reach a critical mass of goodwill.
The direct utility may be limited to a subset of people who may not have room for another console, or are reluctant to pay for a new console if they cannot get some resale value from the current box.
A person might not ever play a 4k bluray in the end, but right now they might be considering it or hope to someday have the setup for it.
There is a product that might match the aspiration or grant the possibility, versus one that denies the chance. Also, those willing to spend for 4K may be few, but they would probably be the ones more willing to evangelize or be enthusiastic with what they've purchased.
From a numbers standpoint, it may not be that many. However, consoles are a luxury good that are often bought for emotional reasons rather than dispassionate evaluation of their likely utility--so live by the sword, die by the sword. The dream scenario is that enough hype or good network effects are focused on a console to encourage sales on a product that would be for the vast majority of the user base be interchangeable with the other.
Hype or positive reception can be a bit like nuclear fusion. You want energy unified and focused at a single point, and you don't want to give too many little opportunities for it to dissipate.
You might have enough slack, which Sony apparently thinks it's banked in terms of 4K bluray.
I've been pondering if the mid-gen consoles have an uphill battle with regard to not being able to gather their own share of hype, without continuously losing a bit of hope or enthusiasm here or there on the "well it would have been nice" or "it's not
that big a deal" or "it's sort of better here" and so on.