Headless systems such as Storyblok have been on everyone's lips for a while now. But it's not always worth using them. Generally speaking, every system has its pros and cons, and headless systems like Storyblok are no exception. In the following I can only speak for Storyblok, but it may also apply to other headless systems.
Firstly, a brief definition or description: In a website that is operated with Storyblok, the content with its data and structures is decoupled from the presentation layer, the frontend. The frontend then retrieves its data via API.

Where Storyblok alone cannot help

Storyblok is responsible for hosting the CMS data, and only for that. This also means that the effort required to implement other services is already an obstacle or additional expense.

An example: Almost every website now has a contact form or you can sign up for a newsletter on the website. However, this has nothing to do with Storyblok and must be considered a separate implementation. This also increases the development effort for the entire website.

Using Stoyblok in a team of developers has its pitfalls. It requires experience to work in a team on the same Storyblok project.

Where Storyblok scores

Developers appreciate Storyblok because the technology used for the front end is freely selectable. As Storyblok makes its data available via CDN (content delivery network), the data is loaded very quickly, regardless of where the website is accessed from.

Content editors appreciate Storyblok's visual editor because it makes editing content very convenient.

Conclusion

If a website is of a certain size, is changed frequently and is possibly maintained by several content editors at the same time, then Storyblok can show its best side.
Conversely, if a website is of a manageable size and is not changed often, but rather serves as a business card on the Internet, then Storyblok should perhaps not be used.