That comparison chart is not very accurate. The Core i7-1250U CPUMark score of 13453 is at 29W (TDP up), not 9W (TDP down), so the performance per watt ratio they're using is inaccurate. Also, if you look at the CPUMark score distributions, you see a bimodal distribution because it mixes the 10 W (MacBook air) and 15W (MacBook Pro) configurations.

The 10W (MacBook Air) variant of the M1 achieves a median CPUMark score of ~14500. That's a lot better than the Intel CPU's 13453 at 29W. Now, if you limit the Intel CPU to a lower TDP by underclocking, the performance per watt can improve substantially (since the efficiency plummets when going for peak clock speeds), but it's still considerably behind the M1.