Especially GPU?
Explain to me what is so "pro" compared to the new Apple laptops? The Surface Book is locked to 16GB of RAM too you know. It is only 13". It only has a GTX 965m 2GB dGPU. Oh and guess what? IT HAS SKYLAKE!!!
I think you missed my discussion point entirely. As the OP first mentioned the dell monitor (and PC likely paired with the monitor), I'm not talking about laptops as 'pro' devices. That's just marketing language, anyways. These laptops are not even close to "pro" workstation specs. And since the products at hand here are Blackmagic tools, it makes sense to address real workstations as the main subjects. The laptops are just eye candy. And to answer your question, nothing really. The surface books and macbook pro's are both just portable, fairly similar, mid-range machines.
My GPU comment was obviously (as most mobile devices have the same top-end 965/395 options) referencing the professional computer/workstation market, in which Apple is vastly behind. Mobile GPU's are fine for laptops, but all up-to-date Apple computers only offer mobile GPU's. As these are blackmagic tools, and no serious grading will be happening on a mobile device with a mobile GPU, workstation users are likely the largest market being targeted. And my point was that it's unlikely anyone would include an old Apple monitor and old Mac Pro in an ad for modern products.
For more clarification on the GPU statement - in case you weren't familiar with the current scenario, literally, the best GPU solution Apple currently offers is the 4+ year old D700 in the Mac Pro. For reference, there are $150 cards now that outperform the D700 (and obviously outperform every other Apple computer that has a mobile 395, etc.) With Vega and more coming soon, Apple will only fall even further behind in the pro market, especially in the field of GPU's.
Long story short, anyone who buys a Mac that is currently available for sale is receiving a computer that will never even reach the GPU performance of a $150, low-mid range PC card. And that should be a pretty big concern in the professional market.