I've been working with Sitecore for over a decade, so its no surprise that I have a bias towards Sitecore. As I've been reviewing headless CMS options on the market and comparing their authoring experiences and content modeling experiences with Sitecore, I've started to notice another compelling reason that Sitecore differentiates.
First, let's get one thing straight. Sitecore is a legacy "coupled" CMS with roots of a monolithic on-prem architecture. However, in recent years Sitecore has added new features and acquired technology that is allowing for more SaaS-based API-driven/headless composable architecture. Ok, I'll stop with the buzzwords.
While I think headless vendors could come close to offering an experience like this, Sitecore being a hybrid headless vendor (that is, a vendor that provides both coupled and de-coupled CMS architecture) really affords them the ability to leverage both their coupled model and headless to provide the best of both worlds.