I assume it's entirely marketing bullshit, whether to say "look how cheap a MBP is!" or to make you think "wow, it's only a little bit more to get the way better model, what a bargain!"
I have 16gb on my M2 Air, and 8gb on my 2014 mini. I’m genuinely surprised at how usable that mini still is. Hell, it’s running Sonoma through OCLP, but it’s only when I boot up the Win11 VM I have installed that it really starts to struggle.
I honestly just made a double pun regarding the new MB Pro with 8gb in the basic configuration and the coming Windows with the 16gb requirement - which both seem strange product decisions with lots of negative customer feedback.