It's more power efficient than the M3, sure, but surely it could've been even more power efficient if it had worse performance simply from having fewer transistors to switch? It would certainly be more environmentally friendly at the very least!
The most environmentally friendly thing to do is to keep your A12Z for as long as you can, ignoring the annual updates. And when the time comes that you must do a replacement, get the most up to date replacement that meets your needs. Change your mindset - you are not required to buy this one, or the next one.
Of course, I'm not buying this one or any other until something breaks. After all, my current A12Z is way too powerful for iPadOS. It just pains me to see amazing feats of hardware engineering like these iPads with M4 be completely squandered by a software stack which doesn't facilitate more demanding tasks than decoding video.
Millions of people will be buying these things regardless of what I'm doing.
They are for those tasks, where you do need high performance. Where you would wait for your device instead. A few tasks require all cpu power you can get, so that is what the performance cores are for. But most of the time, it will consume a fraction of that power.
My whole point is that iPadOS is such that there's really nothing useful to do with that performance. No task an iPad can do requires CPU power (except for maybe playing games but that'll throttle the M4 to hell and back anyway).
