No they are not, especially not with high end CPUs. Tell me one 10900k, 11900k or 5900x normal PC that is working under those constraints.You're underselling the point - that's a massive benefit! Most users are working in that envelope most of the time. Time will tell if the approach is good or bad Vs more normal cores, buts it definitely looks sensible enough on paper. We won't know until we see the real world figures.
I'm actually overselling this and trying to be nice. Switching high powered cores with low powered cores is the worst "benefit" for any high end PC. These CPUs are still limited to 8 large cores, Intel needs to do much better than that. They could have done 12+4 or something like that. (are they forced to use 8 max because of some weird architecture limit?)
Like I said before, this is mostly for either mobile devices like laptops of very niche PCs (power/cooling constrained builds). I'm sure it will shine in some battery tests.