1.fits nicely in pocket. I can sit down comfortably with it in a pair of jeans. No dodgy posture.
2. Won't fall out of my pocket
Its screen is also much less likely to break like has happened with all my old phones when they accidentally fall out of jacket pocket
Also the z-flip battery life is atrocious, and the CPU is old prev gen tech.
I really want a top tier foldable.
At the time I bought the z-flip 3 my understanding was that the tradeoff was unavoidable. My opinion at the time of purchase was that the incremental benefit of the latest version of CPU, camera and battery were pretty marginal relative to the large benefit from the unique form factor.
I'm not currently in the market but that could well have changed if new foldables have since been released.