AnandTech has decent benchmarks for both Tiger Lake [0] and M1 [1].

[0]: https://www.anandtech.com/show/16084/intel-tiger-lake-review...

[1]: https://www.anandtech.com/show/16252/mac-mini-apple-m1-teste...

The outcome seems to depend greatly on the physical design of the laptops. The elsewhere-mentioned Dell XPS 13 has a particularly poor cooling design, which is why I chose the Razer Book instead. Despite being marketed in a very silly way to gamers only, it seems to have competent mechanical design.

Gamers are likely to run their systems with demanding workloads, for hours, with a color-coded performance counter (FPS stat). They'll notice if it throttles. They're particularly demanding customers, and there's quite a bit of competition for their money.

How common are laptops for gamers? I always build my windows boxes but I’m a casual gamer.

I'm not sure. I know they've been getting more popular with the increased power of laptops and the ability to use external GPUs (via Thunderbolt 3). I'd guess desktops are more common, but some people will have both.

The raw CPU performance of the M1 is about 15% faster single core, and 50% faster multicore, while using nearly half as much power.