Genuinely curious: what could you do on this that you couldn't do on iPad?
I am perhaps biased on this issue because I'm still mad about what happened with the Macbook Air (13" in particular). I bought one in 2011 and it was an amazing laptop. It was a sweet spot of compromise on power and portability.
But the best feature was the price: there is a world of difference between a $1300 laptop and a $3500 laptop. Both are reasonable sums of money but the first is infinitely more "replaceable". You don't feel as bad about losing it or having it break.
What came after were much more expensive for features literally nobody wanted (eg loss of ports, loss of MagSafe, a significantly worse keyboard, more expensive repairs, Touch Bar) at a higher price. The 13" MBA languished for years just needing a display upgrade and that's it.
I knew it was the nail in the coffin when the 12" Macbook came out because Apple wouldn't have 11", 12" and 13" SKUs (they also had the 13" MBP by this point) and I was right.
So for me the 12" MBP was everything bad about the new Macbooks with worse performance and a higher price. I didn't (and still don't) really understand who the 12" Macbook solves a problem for.