I don’t find any value in this product ...
You're entitled to
your own opinion, for
your own use case, nobody can argue against this.
... it does not meet any real standards for hi fi listening given that most speakers especially bookshelves are low sensitivity and their real impedance is more near 4 ohms than 8 ohms.
But please, don't try to make an opinion sound like facts. All dynamic speakers are low sensitivity in absolute terms (with efficiency in the one digit % range, usually around 1%). 60 watts are plenty enough for many homes, even more so when a subwoofer with proper bass management is used.
Erin's video has it's issues (in particular his understanding of multi-tone testing is lacking, Audioholics already announced an article explaining this in more detail and
other objective reviewers came to different results), but at least he didn't make the mistake of stating, that the WiiM Amp had problems into 4 ohm speakers. It hasn't, not at all, quite the contrary.
The amp is not linear it cannot perform adequately in low frequencies and users are not satisfied with its power performance.
What you might be refering to as "not linear" is a certain amount of load dependency which is common to all lower and many mid price class D designs. That's not good but also not the end of the world (and it's less of a problem with 4 ohm speakers). Nobody cares about clean power output at 20 Hz with a streamer, DAC, pre-amp and power-amp for 300 bucks, featuring bass management and (soon to come) room correction.
The other stuff you must have read on the Internet. At least on those sites you picked to support your opinion. If this device is not your cup of tea, then be it. That's fine with me. Objectively it's a good device, selling faster than they can make it and providing excellent value and great sounding in many setups. I don't see why it should be replaced. Did I hope for PFFB with the Amp? Yep, sure enoug. But it is still good enough without.
If there is one thing WiiM did wrong then it is letting PCB version 2 hit the shelves. That shouldn't have happened. The reasons are obvious, though.