The natural-language chat box (or voice command) is seductive as an interface because it elides the question of how somebody will use a product. It makes a product that uses it seem more
potentially capable, because you can imagine asking it anything (we all remember the sense of possibility in the first Zork-style games). If the user was provided with an affordance to understand the range of capabilities of the product, they might realize it's too limited for them, or realize that their use case is served by something else.
The chat/voice interface is like Skinner's Box: we keep "using" because we don't know what will work and what won't, and when something works it seems magical. And it keeps being pushed on customers because it's beneficial for corporations: customers will fruitlessly navigate chat support rather than realizing they should give up and call, businesses will invest in products with open-ended interfaces because they can convince themselves it's flexible enough for their needs.