The main advantage is the CPU. The M1/M2 are blazingly fast, and basically never get even warm. I have to _really_ crunch the machine to even hear the faintest hum of the fan. Battery lasts for ever, it's like a phone, charge once a day if that.
Before getting my 2021 16" MBP with a M1 Max, I'd read comments like yours and get the idea that I'd be able to encode video without it getting warm :-P This is not the case, at least not with the M1 Max.
It does get warm if we push it hard for a few minutes. This could be easily avoided if Apple started the fans at low speeds earlier, but instead they let the SoC run at 80-90ºC for 2 or 3 minutes before the fans kick in at low speeds and that heat needs to go somewhere. There are 3rd party apps that let you control fan speeds, which is what I do.
With this said, coming from a 2019 16" MBP (Intel) it was a huuuge improvement. The damn thing would get warm doing basic tasks. At full power, it would throttle even with the fans at 100% and because the Intel processor was allowed to use more than the 100W the computer could take, any very long tasks would drain the battery. M1/M2 macs are nothing like that.
According to apple themselves the M2 is slower than current intel or amd chips, though not by much. And you are much more limited on RAM and on storage and on GPU performance.
The power consumption under load is impressive though (about half).
Modern CPUs are more than quick enough for my purposes. If you're compiling huge amounts of C/C++/Rust, I see why a powerful CPU might be nice -- still, at my job we have a lot of CI pipelines that just run in the cloud, sidestepping the issue completely.
For normal text editing, shell use, web browsing, IDEs, etc. my i7 is barely even challenged. And any game that can run with my Quadro GPU won't use more cycles than my CPUs got in it.
I do agree the battery life of M1 is quite nice though. I basically keep my laptop plugged in all day so it's not really an issue for me.
In an ideal market, you could buy a T480 with an M2 CPU. Which would be a much better laptop, for a much better price. It's only due to market distortions due to big players trying to be anticompetitive that we're stuck with this choice.
