Why Intel is playing that game, I can’t imagine since it’s a really bad look, but that isn’t the subject of this post.
Intel are playing that game because they’re still behind in power efficiency. It’s part process and part architecture, but in practice the result is simply that for any given power limit zen4 will outperform 12th gen and its various refreshes. Heterogeneous architecture ought to give Intel a slight power advantage outside benchmarks and chiplets put AMD at a disadvantage, but in practice e-cores are more space efficient than they are energy efficient (letting them put more cores in a smaller area die and offsetting the cost of large monolithic dies) and TSMC 5nm beats Intel 7nm. Intel are catching up, but it will take time, and until they do become competitive in efficiency they prefer to market on pure performance (because their performance/W is quite unimpressive)
The Lenovo Ideapad 5 is still going to be a better purchase. 32GB RAM at 6400MT/s, 7840 processor with the 780M, and actually reasonable storage (a terabyte, not perfect but at least it’s not the useless 512GB most standard laptops offer).